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    Somobrata Acharya, Bidisa Das, Umamahesh Thupakula, Katsuhiko Ariga, D.D. Sarma, Jacob Israelachvili & Yuval Golan A Bottom-Up Approach toward Fabrication of Ultrathin PbS Sheets

    [Abstract] [BibTeX]

    		 2013 Nano Lett.
    Vol. 13(2)Nano Letters, 409-415     		 DOI  
    Abstract: Two-dimensional (2D) sheets are currently in the spotlight of nanotechnology owing to high-performance device fabrication possibilities. Building a free-standing quantum sheet with controlled morphology is challenging when large planar geometry and ultranarrow thickness are simultaneously concerned. Coalescence of nanowires into large single-crystalline sheet is a promising approach leading to large, molecularly thick 2D sheets with controlled planar morphology. Here we report on a bottom-up approach to fabricate high-quality ultrathin 2D single crystalline sheets with well-defined rectangular morphology via collective coalescence of PbS nanowires. The ultrathin sheets are strictly rectangular with 1.8 nm thickness, 200-250 nm width, and 3-20 micrometer length. The sheets show high electrical conductivity at room and cryogenic temperatures upon device fabrication. Density functional theory (DFT) calculations reveal that a single row of delocalized orbitals of a nanowire is gradually converted into several parallel conduction channels upon sheet formation, which enable superior in-plane carrier conduction.
    Keywords: ATK; Application; nanowires; ultrathin sheet; coalescence; activation energy; DFT calculations; transport; metal-insulator-transition; Langmuir monolayers; ballistic transport; oriented attachment; suspended graphene; room-temperature; nanowires; superlattices; nanocrystals
    Area: nanowires
    BibTeX: 
    @article{Acharya2013,
  author = {Acharya, Somobrata and Das, Bidisa and Thupakula, Umamahesh and Ariga, Katsuhiko and Sarma, D. D. and Israelachvili, Jacob and Golan, Yuval},
  title = {A Bottom-Up Approach toward Fabrication of Ultrathin PbS Sheets},
  booktitle = {Nano Letters},
  journal = {Nano Lett.},
  publisher = {American Chemical Society},
  year = {2013},
  volume = {13},
  number = {2},
  pages = {409--415},
  doi = {http://dx.doi.org/10.1021/nl303568d}
}
    Zhaoqiang Bai, Yongqing Cai, Lei Shen, Guchang Han & Yuanping Feng High-performance giant-magnetoresistance junctions based on the all-Heusler architecture with matched energy bands and Fermi surfaces

    [Abstract] [BibTeX]

    		 2013 Applied Physics Letters
    Vol. 102(15), 152403     		 DOI  
    Abstract: We present an all-Heusler architecture which could be used as a rational design scheme for achieving high spin-filter efficiency in the current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices. A Co2MnSi/Ni2NiSi/Co2MnSi trilayer stack is chosen as the prototype of such an architecture, of which the electronic structure and magnetotransport properties are systematically investigated by first principles approaches. Well matched energy bands and Fermi surfaces between the all-Heusler electrode-spacer pair are found, which, in combination with the electrode half-metallicity, indicate large bulk and interfacial spin-asymmetry, high spin-filter efficiency, and consequently good magnetoresistance performance. Transport calculations further confirm the superiority of the all-Heusler architecture over the conventional Heusler/transition-metal structure by comparing their transmission coefficients and interfacial resistances of parallel conduction electrons, as well as the macroscopic current-voltage characteristics. We suggest future theoretical and experimental efforts in developing high-performance all-Heusler CPP-GMR junctions for the read heads of the next generation high-density hard disk drives.
    Keywords: ATK; Application; interfaces; spin; semi; ab initio calculations, band structure, cobalt alloys, Fermi surface, giant magnetoresistance, manganese alloys, multilayers, nickel alloys, silicon alloys, spin systems
    Area: interfaces; spin; semi; nvm
    BibTeX: 
    @article{Bai2013a,
  author = {Bai, Zhaoqiang and Cai, Yongqing and Shen, Lei and Han, Guchang and Feng, Yuanping},
  title = {High-performance giant-magnetoresistance junctions based on the all-Heusler architecture with matched energy bands and Fermi surfaces},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2013},
  volume = {102},
  number = {15},
  pages = {152403},
  doi = {http://dx.doi.org/10.1063/1.4802581}
}
    S. Barzilai, F. Tavazza & L.E. Levine First-principle modeling of gold adsorption on BeO (0001)

    [Abstract] [BibTeX]

    		 2013 Surface Science
    Vol. 609(0), 39-43     		 DOI URL 
    Abstract: Gold nanowire chains are considered a good candidate for nanoelectronic devices since they exhibit remarkable structural and electrical properties. For practical engineering devices, alpha-wurtzite BeO may be a useful platform for supporting these nanowires, since the atom separation of the BeO (0001) surface is compatible with the Au-Au atom spacing. However, its influence on the nanowire conductivity is unknown. Here, ab initio simulations of adsorption of one gold atom on cleaved BeO (0001) surfaces have been performed to find the most favorable adsorption site. An attractive adsorption was obtained for all the studied sites, but the most favorable site was above the oxygen for the O-terminated surface and above the Be-Be bridge for the Be-terminated surface. A relatively high electron density is observed in the AuO and AuBe bonds, and the local density of states exhibits high peaks in the vicinity of the Fermi energy.
    Keywords: ATK; Application; BeO; ab-initio calculations, adsorption, substrate; geometry optimization; band-structure; surfaces; conductance; molecules; chains; oxide
    Area: nanowires
    BibTeX: 
    @article{Barzilai2013a,
  author = {Barzilai, S. and Tavazza, F. and Levine, L.E.},
  title = {First-principle modeling of gold adsorption on BeO (0001)},
  journal = {Surface Science},
  year = {2013},
  volume = {609},
  number = {0},
  pages = {39--43},
  url = {http://www.sciencedirect.com/science/article/pii/S0039602812003871},
  doi = {http://dx.doi.org/10.1016/j.susc.2012.10.017}
}
    Nikolai Lebedev, Igor Griva & Anders Blom Internal Control of Electron Transfer through a Single Iron Atom by Chelating Porphyrin

    [Abstract] [BibTeX]

    		 2013 J. Phys. Chem. C
    Vol. 117(14)The Journal of Physical Chemistry C, 6933-6939     		 DOI URL 
    Abstract: Construction of efficient and highly integrated electronic devices is the main challenge and goal of nanoelectronics. The main problem in the construction of such devices is the fusion between conducting and controlling parts of the device, substantially reducing the efficiency of regulation. To approach the problem we study the electron transfer through a carbon nanotube (CNT)-histidine-heme-histidine-CNT conjugate with an orthogonal porphyrin orientation relative to the CNT electrodes. Using density functional theory and nonequilibrium Green's function calculations we show that at low bias the CNT molecular orbitals are electronically coupled only to the Fe atom but uncoupled from the tetrapyrrole ring of the porphyrin. We found that at low bias the electrons pass exclusively through the central Fe atom of the porphyrin, but at higher bias they are partially scattered by the tetrapyrrole ring, leading to a reduction of the total current through the molecule (negative differential resistance). This allows for keeping the electron flow through the device at a specific level and for controlling the current through the device by the redox state of the tetrapyrrole ring. In the orthogonal orientation, neither of the porphyrin side groups directly participates in the electron transfer through the heme and can thus be used for porphyrin binding and orientation to proteins or electrodes. These results open the possibility for the construction of a highly integrated electronic field effect transistor in a single molecule with controllable electron transfer through individual iron atoms.
    Keywords: ATK; Application; molecular electronics; nanotube; negative differential resistance; histidine; heme; porphyrin;
    Area: molecular electronics
    BibTeX: 
    @article{Lebedev2013,
  author = {Lebedev, Nikolai and Griva, Igor and Blom, Anders},
  title = {Internal Control of Electron Transfer through a Single Iron Atom by Chelating Porphyrin},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2013},
  volume = {117},
  number = {14},
  pages = {6933--6939},
  url = {http://dx.doi.org/10.1021/jp311686c},
  doi = {http://dx.doi.org/10.1021/jp311686c}
}
    Lili Lin, Jun Jiang & Yi Luo Elastic and inelastic electron transport in metal-molecule(s)-metal junctions

    [Abstract] [BibTeX]

    		 2013 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 47(0), 167-187     		 DOI URL 
    Abstract: An overview of studies on elastic and inelastic electron transport properties of molecular junction devices is presented. The development of the experimental fabrication and characterization of molecular junctions as well as the corresponding theoretical modeling is briefly summarized. The functions of molecular devices are generally governed by the intrinsic structure-property relationships, and strongly affected by various environment factors including temperature, solvent and intermolecular interactions. Those detailed structural and environmental information could be probed by a powerful tool of inelastic electron tunneling spectroscopy, for which the theoretical modeling becomes particularly important. With many successful examples, it is demonstrated that the combination of theoretical simulations and experimental measurements can help not only to understand the electron-phonon interaction, but more importantly also to accurately determine the real configurations of molecules inside the junctions.
    Keywords: ATK; Application; Review; molecular electronics; single-molecule conductance; self-assembled monolayers; current-voltage characteristics; carbon nanotube electrodes; tunneling spectroscopy; charge-transport; room-temperature; distance-dependence; quantum transport; organic-molecules
    Area: molecular electronics
    BibTeX: 
    @article{Lin2013,
  author = {Lin, Lili and Jiang, Jun and Luo, Yi},
  title = {Elastic and inelastic electron transport in metal-molecule(s)-metal junctions},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2013},
  volume = {47},
  number = {0},
  pages = {167--187},
  url = {http://www.sciencedirect.com/science/article/pii/S1386947712004213},
  doi = {http://dx.doi.org/10.1016/j.physe.2012.10.017}
}
    Y.L. Liu, X.Q. Deng & X.C. Duan The electronic transport properties for a single-wall ZnO nanotube with different coupling interfaces

    [Abstract] [BibTeX]

    		 2013 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 52(0), 21-26     		 DOI URL 
    Abstract: The transport properties of a single-wall ZnO nanotube contacted with two Au (Al or Cu ) electrodes are investigated by a theoretical approach. Our results suggest the contact resistance for ZnO nanotube connected with Au electrodes is the largest one as compared with Al and Cu acting as electrodes. The local density of states (LDOS) near the ZnO nanotube/Cu(Al) interface shows the strong electronic interaction. Also shown is that for Au-ZnO system, we can observe a best rectifying performance, the next is the Al-ZnO system, and the third is Cu-ZnO system. This rectification is also fully rationalized by the calculated transmission spectra, the spatial distribution of the lowest unoccupied molecular orbital and highest occupied molecular orbital states, and the electrostatic potential distribution.
    Keywords: ATK; Application; ZnO nanotube; rectification; coupling interface; density functional theory; contact resistance
    Area: nanotubes
    BibTeX: 
    @article{Liu2013a,
  author = {Liu, Y.L. and Deng, X.Q. and Duan, X.C.},
  title = {The electronic transport properties for a single-wall ZnO nanotube with different coupling interfaces},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2013},
  volume = {52},
  number = {0},
  pages = {21--26},
  url = {http://www.sciencedirect.com/science/article/pii/S1386947713000817},
  doi = {http://dx.doi.org/10.1016/j.physe.2013.03.016}
}
    Nadine Seidel, Torsten Hahn, Simon Liebing, Wilhelm Seichter, Jens Kortus & Edwin Weber Synthesis and properties of new 9,10-anthraquinone derived compounds for molecular electronics

    [Abstract] [BibTeX]

    		 2013 New J. Chem.
    Vol. 37(3), 601-610     		 DOI  
    Abstract: Fourteen new derivatives of 9,10-anthraquinone or 9,10-dimethoxyanthracene were designed, synthesised and characterised. Regarding the structure, the compounds are [small pi]-conjugated (cross and linear, respectively) and feature thiophene terminated side arms attached to five different positions of the anthraquinone or anthracene core. The synthesis of the compounds involves a cross-coupling procedure in the key reaction steps. Crystal structures of compounds 5 and 19 have been studied. The thiophene containing title compounds 1-5 can be reduced and oxidised by a two step redox process. The electrochemical parameters have been analysed by cyclic voltammetry (CV). Theoretical calculations in the framework of all-electron density functional theory (DFT) were used to investigate the electronic structure of the individual free molecules. Furthermore, calculations of the transport properties of model devices containing compounds 1-3 and respective reduced hydroquinone derivatives assembled at Au(111) electrodes were carried out to evaluate their potential for the application as redox-active switches.
    Keywords: ATK; Application; molecular electronics; alligator clips; electrochemical properties; anion-radicals; anthraquinone; derivatives; dimethylformamide; approximation; intensities; components; efficient
    Area: molecular electronics
    BibTeX: 
    @article{Seidel2013,
  author = {Seidel, Nadine and Hahn, Torsten and Liebing, Simon and Seichter, Wilhelm and Kortus, Jens and Weber, Edwin},
  title = {Synthesis and properties of new 9,10-anthraquinone derived compounds for molecular electronics},
  journal = {New J. Chem.},
  publisher = {The Royal Society of Chemistry},
  year = {2013},
  volume = {37},
  number = {3},
  pages = {601--610},
  doi = {http://dx.doi.org/10.1039/C2NJ40772H}
}
    Colin Van Dyck, Victor Geskin, Auke J. Kronemeijer, Dago M. de Leeuw & Jerome Cornil Impact of derivatization on electron transmission through dithienylethene-based photoswitches in molecular junctions

    [Abstract] [BibTeX]

    		 2013 Phys. Chem. Chem. Phys.
    Vol. 15(12), 4392-4404     		 DOI  
    Abstract: We report a combined Non-Equilibrium Green's Function - Density Functional Theory study of molecular junctions made of photochromic diarylethenes between gold electrodes. The impact of derivatization of the molecule on the transmission spectrum is assessed by introducing: (i) substituents on the diarylethene core; and (ii) linker substituents between the gold surface and the diarylethene. We illustrate that substituents on the core shift considerably the HOMO/LUMO level energies in gas phase but do not change the I-V characteristics of the molecular junctions; this behaviour has been rationalized by establishing links between the transmission spectrum and interfacial electronic reorganization upon chemisorption. In contrast, the different linker substituents under study modulate the conductivity of the junction by changing the degree of orbital hybridization with the metallic electrodes and the degree of orbital polarization.
    Keywords: ATK; Application; molecular electronics; generalized gradient approximation; quantum transport; single-molecule; optical-properties; gold electrodes; devices; conductance; diarylethenes; density; isomerization
    Area: molecular electronics
    BibTeX: 
    @article{VanDyck2013,
  author = {Van Dyck, Colin and Geskin, Victor and Kronemeijer, Auke J. and de Leeuw, Dago M. and Cornil, Jerome},
  title = {Impact of derivatization on electron transmission through dithienylethene-based photoswitches in molecular junctions},
  journal = {Phys. Chem. Chem. Phys.},
  publisher = {The Royal Society of Chemistry},
  year = {2013},
  volume = {15},
  number = {12},
  pages = {4392--4404},
  doi = {http://dx.doi.org/10.1039/C3CP44132F}
}
    YaQin Wang, YueE. Xie, ZaiLan Zhang, Ye Zhang & YuanPing Chen Spin-polarized transport in zigzag graphene nanoribbons adsorbing nonmagnetic atomic chain

    [Abstract] [BibTeX]

    		 2013 European Physical Journal B
    Vol. 86(2)The European Physical Journal B, 1-6     		 DOI  
    Abstract: The spin-polarized transport properties of nonmagnetic (metallic Al and nonmetallic C) atomic chains adsorbed on zigzag graphene nanoribbons (ZGNRs) are investigated by the density functional theory (DFT) combined with the nonequilibrium Green's function method. We find that the spin polarization of ZGNRs is sensitive to the adsorption sites and atomic types of the chains. As an Al chain is adsorbed on the middle of ZGNR, no spin-polarized transport arises. As the Al chain is adsorbed on the edge of ZGNR, high spin polarization is produced around the Fermi level. The different transport behaviors are originated from the fact that the edge adsorption of Al chain breaks the magnetization symmetry of two edges while the middle adsorption of Al chain only modifies the magnetizations of two edges equally. More prominent spin polarization is generated as a C chain is adsorbed on the edge of ZGNR. The complete spin polarization emerges not only around the Fermi level but also far from the Fermi level, owing to the edge states and the localized states. These results indicate that one can effectively modulate the spin-polarized transports of ZGNRs through adsorbing different nonmagnetic atomic chains.
    Keywords: ATK; Application; graphene nanoribbon; spin; adsorbed atoms; doping; spin-polarized transport
    Area: graphene; spin
    BibTeX: 
    @article{Wang2013a,
  author = {Wang, YaQin and Xie, YueE. and Zhang, ZaiLan and Zhang, Ye and Chen, YuanPing},
  title = {Spin-polarized transport in zigzag graphene nanoribbons adsorbing nonmagnetic atomic chain},
  booktitle = {The European Physical Journal B},
  journal = {European Physical Journal B},
  publisher = {Springer-Verlag},
  year = {2013},
  volume = {86},
  number = {2},
  pages = {1-6},
  doi = {http://dx.doi.org/10.1140/epjb/e2012-30912-5}
}
    Huaping Xiao, Chuanxiao Zhang, Kaiwang Zhang, Lizhong Sun & Jianxin Zhong Tunable differential conductance of single wall C/BN nanotube heterostructure

    [Abstract] [BibTeX]

    		 2013 Journal of Molecular Modeling
    Vol. 2013Journal of Molecular Modeling, 1-5     		 DOI  
    Abstract: The transport properties and differential conductance of the heterostructures constructed by (5,5) single wall carbon nanotube (SWCNT) and (5,5) single wall boron nitride nanotube (SWBNNT) are investigated using density functional theory in combination with non-equilibrium Green's functions. We find that the transmission conductance of (5,5) BN/C nanotube heterostructure is not only continually depressed as the BNNT region increases but also the drop of the conductance is uniform in the energy window (-1.43 eV, 1 eV), which leads to linear I-V dependence for the systems when the bias is within this energy range. Moreover, the differential conductance linearly decreases when n<=3 but exponentially decreases when n>=3 for (5,5)(BN) n /C heterostructure. Such tunable differential conductance of (5,5) BN/C nanotube heterostructure mainly derives from the blockage of the transport channels induced by the semiconductive BN segment.
    Keywords: ATK; Application; C/BN nanotube heterostructure; differential conductance; transport property
    Area: nanotubes
    BibTeX: 
    @article{Xiao2013a,
  author = {Xiao, Huaping and Zhang, Chuanxiao and Zhang, Kaiwang and Sun, Lizhong and Zhong, Jianxin},
  title = {Tunable differential conductance of single wall C/BN nanotube heterostructure},
  booktitle = {Journal of Molecular Modeling},
  journal = {Journal of Molecular Modeling},
  publisher = {Springer-Verlag},
  year = {2013},
  volume = {2013},
  pages = {1-5},
  doi = {http://dx.doi.org/10.1007/s00894-013-1823-y}
}
    Chengyu Yang & Quanfang Chen Electronic structure and transport properties of carbon nanotube adsorbed with a copper chain

    [Abstract] [BibTeX]

    		 2013 International Journal of Smart and Nano Materials
    Vol. 2013International Journal of Smart and Nano Materials, 1-7     		 DOI  
    Abstract: The authors have studied the electronic structure and transport properties of hybrid nanowires made of a copper chain adsorbed on a single-wall carbon nanotube (CNT) using first principle methods. Results have shown that after the adsorption of the Cu chain, the density of states and the transmission coefficients of the CNT (5, 5)/Cu nanowire have been increased, while the band gap of CNT (10, 0)/Cu have been significantly reduced. These results imply that the conductivity of CNTs, either metallic or semiconducting, have been enhanced by the adsorption of a copper chain. These hybrid nanowires with enhanced conductivity may be suitable for nanoelectronics.
    Keywords: ATK; Application; nanotubes; atomic chain; nanowire
    Area: nanotubes
    BibTeX: 
    @article{Yang2013,
  author = {Yang, Chengyu and Chen, Quanfang},
  title = {Electronic structure and transport properties of carbon nanotube adsorbed with a copper chain},
  booktitle = {International Journal of Smart and Nano Materials},
  journal = {International Journal of Smart and Nano Materials},
  publisher = {Taylor & Francis},
  year = {2013},
  volume = {2013},
  pages = {1--7},
  doi = {http://dx.doi.org/10.1080/19475411.2013.782906}
}
    P. Zhao & D.S. Liu Negative differential resistance behavior in molecular devices based on carbon nanotubes: Effects of chirality and electrode–electrode distance

    [Abstract] [BibTeX]

    		 2013 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 47(0), 224-228     		 DOI URL 
    Abstract: Using first-principles density functional theory and real-space non-equilibrium Green′s function formalism for quantum transport calculation, we investigate all-carbon mechanically controlled molecular devices which consists of only two (5,5) armchair and two (6,0) zigzag single-walled carbon nanotubes (SWCNTs) opposing one another. Our results show that the chirality of SWCNTs and the electrode–electrode distance have crucial effects on the electronic transport properties of such systems. When the right SWCNT electrode is mechanically pushed forward along its axial direction, obvious negative differential resistance behaviors are observed in the zigzag system, but not in the armchair case.
    Keywords: ATK; Application; molecular electronics; transport-properties; field-emission; wire; conductance; junction; graphene; state
    Area: molecular electronics
    BibTeX: 
    @article{Zhao2013e,
  author = {Zhao, P. and Liu, D.S.},
  title = {Negative differential resistance behavior in molecular devices based on carbon nanotubes: Effects of chirality and electrode–electrode distance},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2013},
  volume = {47},
  number = {0},
  pages = {224--228},
  url = {http://www.sciencedirect.com/science/article/pii/S1386947712004493},
  doi = {http://dx.doi.org/10.1016/j.physe.2012.11.008}
}
    Vladimir Kolchuzhin, Jan Mehner, Milind Shende, Erik Markert, Ulrich Heinkel, Christian Wagner & Thomas Gessner System Level Modelling of CNT based Mechanical Sensor

    [Abstract] [BibTeX]

    		 2013 Chemnitzer Fachtagung Mikrosystemtechnik
    Vol. 11, 1-6     		 URL 
    Abstract: This article presents a system level model of carbon nanotube (CNT) based mechanical sensor, which consists of micro-electro-mechanical (MEMS) platform that is served to actuate single-axis force and single CNT is placed between the movable and fixed electrodes. The change in conductivity of CNT, when strain is applied, is used to measure force or displacement. The simulation of the whole sensor element will be achieved by using the framework of hardware description languages (VHDL-AMS and SystemC-AMS) that uses compact models to describe sub-elements performing heterogeneous functions. The CNT piezoresistive compact model presented in the article is based on the analytical model and the simulations results from density functional theory (DFT). The macromodel of the MEMS platform is build using mode superposition technique. The results of the system simulations are presented and discussed in the article.
    Keywords: ATK; Application; nanotube; piezoelectric effect; mechanical sensor; compact model; DFT;
    Area: nanotubes
    BibTeX: 
    @article{Kolchuzhin2013,
  author = {Kolchuzhin, Vladimir and Mehner, Jan and Shende, Milind and Markert, Erik and Heinkel, Ulrich and Wagner, Christian and Gessner, Thomas},
  title = {System Level Modelling of CNT based Mechanical Sensor},
  journal = {Chemnitzer Fachtagung Mikrosystemtechnik},
  year = {2013},
  volume = {11},
  pages = {1-6},
  url = {http://www.researchgate.net/publication/235338375_System_Level_Modelling_of_CNT_based_Mechanical_Sensor/file/32bfe5110c3b56b43e.pdf}
}
    Yukihito Matsuura & Toshifumi Morioka Quantum Transport in mu-Cyclopentadienyl Indium Complex

    [Abstract] [BibTeX]

    		 2013 Molecular Crystals and Liquid Crystals
    Vol. 574(1)Molecular Crystals and Liquid Crystals, 135-142     		 DOI  
    Abstract: The electronic structure and conductance of a mu-cyclopentadienyl indium (Cp-In) multidecker complex have been examined by using the density functional theory (DFT). The electrical conduction of the complex between gold electrodes is investigated by using Green's function formalism. The one-dimensional band structure exhibited semiconducting properties. The Cp5In4- complex, which had a long molecular length, between gold electrodes, exhibited low electrical conduction. On the other hand, the Cp3In2- complex between the gold electrodes had transmission at the Fermi level. The I-V curves suggest the intrinsic characteristics of semiconducting properties and the suppression of strong tunneling effect.
    Keywords: ATK; Application; molecular electronics
    Area: molecular electronics
    BibTeX: 
    @article{Matsuura2013a,
  author = {Matsuura, Yukihito and Morioka, Toshifumi},
  title = {Quantum Transport in mu-Cyclopentadienyl Indium Complex},
  booktitle = {Molecular Crystals and Liquid Crystals},
  journal = {Molecular Crystals and Liquid Crystals},
  publisher = {Taylor & Francis},
  year = {2013},
  volume = {574},
  number = {1},
  pages = {135--142},
  doi = {http://dx.doi.org/10.1080/15421406.2012.763016}
}
    Xiaozan Wu, Guanghui Huang, Qingbin Tao & Hui Xu Effect of boron/nitrogen codoping on transport properties of C60 molecular devices

    [Abstract] [BibTeX]

    		 2013 J. Cent. South Univ.
    Vol. 20, 889-893     		 DOI  
    Abstract: By using nonequilibrium Green's function method and firstprinciples calculations, the electronic transport properties of doped C60 molecular devices were investigated. It is revealed that the C60 molecular devices show the metal behavior due to the interaction between the C60 molecule and the metal electrode. The current-voltage curve displays a linear behavior at low bias, and the currents have the relation of M1>M3>M4>M2 when the bias voltage is lower than 0.6 V. Electronic transport properties are affected greatly by the doped atoms. Negative differential resistance is found in a certain bias range for C60 and C58BN molecular devices, but cannot be observed in C59B and C59N molecular devices. These unconventional effects can be used to design novel nanoelectronic devices.
    Keywords: ATK; Application; negative differential resistance; molecular device; electronic transport property; first-principles calculation
    Area: molecular electronics
    BibTeX: 
    @article{Wu2013a,
  author = {Wu, Xiaozan and Huang, Guanghui and Tao, Qingbin and Xu, Hui},
  title = {Effect of boron/nitrogen codoping on transport properties of C60 molecular devices},
  journal = {J. Cent. South Univ.},
  year = {2013},
  volume = {20},
  pages = {889-893},
  doi = {http://dx.doi.org/10.1007/s1177101315623}
}
    P. Zhao, D.S. Liu, S.J. Li & G. Chen Modulation of rectification and negative differential resistance in graphene nanoribbon by nitrogen doping

    [Abstract] [BibTeX]

    		 2013 Physics Letters A
    Vol. 377(15), 1134-1138     		 DOI  
    Abstract: Abstract By applying the nonequilibrium Green's function formalism combined with density functional theory, we have investigated the electronic transport properties of two nitrogen-doped armchair graphene nanoribbon-based junctions M1 and M2. In the left part of M1 and M2, nitrogen atoms are doped at two edges of the nanoribbon. In the right part, nitrogen atoms are doped at one edge and at the center for M1 and M2, respectively. Obvious rectifying and negative differential resistance behaviors are found, which are strongly dependent on the doping position. The maximum rectification and peak-to-valley ratios are up to the order of 10^4 in M2.
    Keywords: ATK; Application; graphene nanoribbon; electronic transport; rectification; negative differential resistance; NDR;
    Area: graphene
    BibTeX: 
    @article{Zhao2013b,
  author = {Zhao, P. and Liu, D.S. and Li, S.J. and Chen, G.},
  title = {Modulation of rectification and negative differential resistance in graphene nanoribbon by nitrogen doping},
  journal = {Physics Letters A},
  year = {2013},
  volume = {377},
  number = {15},
  pages = {1134--1138},
  doi = {http://dx.doi.org/10.1016/j.physleta.2013.02.048}
}
    JingFen Zhao, ChuanLu Yang, MeiShan Wang & Jie Ma First-principles analysis of the effect of contact sites on electronic transport properties of diaminofluorene

    [Abstract] [BibTeX]

    		 2013 Physica B: Condensed Matter
    Vol. 417(0), 70-74     		 DOI  
    Abstract: The effects of atop, hollow, bridge and adatom contact sites on the electronic transport properties of a single diaminofluorene molecule connected to gold electrodes are studied by using nonequilibrium Green's functions in combination with the density functional theory. Computational results were analyzed to identify the contact site utilized in the experiment of Lu et al. (2009) [26]. Current-voltage curves were also examined. The rectifying behavior of diaminofluorene was observed in the atop, hollow and bridge contact sites. The highest occupied molecular orbital, the lowest unoccupied molecular orbital and transmission spectra were used in determining the various electronic transport properties of diaminofluorene.
    Keywords: ATK; Application; rectifying behavior; contact sites; nonequilibrium Green's function; density functional theory; electronic transport; molecular electronics
    Area: molecular electronics
    BibTeX: 
    @article{Zhao2013c,
  author = {Zhao, JingFen and Yang, ChuanLu and Wang, MeiShan and Ma, Jie},
  title = {First-principles analysis of the effect of contact sites on electronic transport properties of diaminofluorene},
  journal = {Physica B: Condensed Matter},
  year = {2013},
  volume = {417},
  number = {0},
  pages = {70--74},
  doi = {http://dx.doi.org/10.1016/j.physb.2013.02.007}
}
    P. Zhao, D.S. Liu & G. Chen Effect of mono-vacancy on transport properties of zigzag carbon- and boron-nitride-nanotube heterostructures

    [Abstract] [BibTeX]

    		 2013 Solid State Communications
    Vol. 160(0), 13-16     		 DOI  
    Abstract: On the basis of first-principles density functional theory and non-equilibrium Green's function technique, we have investigated the effects of a mono-vacancy on the electronic transport properties of the carbon nanotube/boron nitride nanotube heterostructures. The results show that the electronic transport properties are strongly dependent on the position of the mono-vacancy, and the negative differential resistance and rectifying performances can be strengthened or weakened alternately with the position change of the mono-vacancy. Moreover, the performance change is more significant when the mono-vacancy occurs on the carbon nanotube part. These interesting phenomena are explained in terms of the evolution of the transmission spectrum with applied bias combined with molecular projected self-consistent Hamiltonian states analysis.
    Keywords: ATK; Application; vacancy electronic transport; negative differential resistance; rectifying; molecular electronics
    Area: molecular electronics
    BibTeX: 
    @article{Zhao2013d,
  author = {Zhao, P. and Liu, D.S. and Chen, G.},
  title = {Effect of mono-vacancy on transport properties of zigzag carbon- and boron-nitride-nanotube heterostructures},
  journal = {Solid State Communications},
  year = {2013},
  volume = {160},
  number = {0},
  pages = {13--16},
  doi = {http://dx.doi.org/10.1016/j.ssc.2013.02.007}
}
    Bagavathi Chandrasekara Nanotransistors from metal and metalloid compound nanotubes

    [Abstract] [BibTeX]

    		 2013 International Journal of Scientific & Engineering Research
    Vol. 4(2), 1-4     		 URL 
    Abstract: The escalating trend of chip integration and miniaturization has dared the designers to seek to a nascent phenomenon to save the Moore's law. Due to continuous reduction in device size, the so-far-unseen quantum effects have dominated the device physics. The solution to this crisis is nanoelectronics. Nano structures are used to develop new devices by utilizing the quantum effects. III group compounds have been known for their special properties as semiconductors in electronics. By including nanoscale nature with III group compounds, greater advantages can be obtained. III group nitride nanotubes have been investigated in many works. The nanotubes under discussion are boron nitride nanotubes and gallium nitride nanotubes. The phenomenon used for analysis in this work is Density Functional Theory (DFT). The characteristics of a device can be deduced from the electronic cloud structure around the device through density functional theory. In this work, III group nitride nanotubes are employed as transistor channels and their characteristics are scrutinized through simulation studies.
    Keywords: ATK; Application; transistor; boron-nitride; nanotube; gallium nitride; nanotube transistor; third group nanotubes; density functional theory; simulation of nanomaterials
    Area: nanotubes
    BibTeX: 
    @article{Chandrasekara2013,
  author = {Bagavathi Chandrasekara},
  title = {Nanotransistors from metal and metalloid compound nanotubes},
  journal = {International Journal of Scientific & Engineering Research},
  year = {2013},
  volume = {4},
  number = {2},
  pages = {1-4},
  url = {http://www.ijser.org/researchpaper/NANOTRANSISTORS-FROM-METAL-AND-METALLOID-COMPOUND-NANOTUBES.pdf}
}
    Pengwei Li, Zhi Yang, Wendong Zhang & Shijie Xiong The magnetic properties and spin-filter effects of manganese-borazine sandwich clusters

    [Abstract] [BibTeX]

    		 2013 Journal of Molecular Structure
    Vol. 1038(0), 1-7     		 DOI URL 
    Abstract: In present paper, detailed investigations on the magnetic and quantum transport properties of Mn_n(B_3N_3H_6)_n+1 (n = 1-4) sandwich clusters were performed by using density functional theory and non-equilibrium Green's function technique. The calculated results show that these clusters are stable and adopt ferromagnetic orders as the ground states. When coupled to Ni electrodes, the sandwiches could exhibit novel quantum transport properties such as high spin-filter capabilities and negative differential resistance effects, indicating that these sandwich systems could be viewed as a new kind of spin filter.
    Keywords: ATK; Application; molecular electronics; sandwich; cluster; spin filter
    Area: molecular electronics; spin
    BibTeX: 
    @article{Li2013a,
  author = {Li, Pengwei and Yang, Zhi and Zhang, Wendong and Xiong, Shijie},
  title = {The magnetic properties and spin-filter effects of manganese-borazine sandwich clusters},
  journal = {Journal of Molecular Structure},
  year = {2013},
  volume = {1038},
  number = {0},
  pages = {1--7},
  url = {http://www.sciencedirect.com/science/article/pii/S0022286013000331},
  doi = {http://dx.doi.org/10.1016/j.molstruc.2013.01.022}
}
    Qing-Qing Sun, Yong-Jun Li, Jin-Lan He, Wen Yang, Peng Zhou, Hong-Liang Lu, Shi-Jing Ding & David Wei Zhang The physics and backward diode behavior of heavily doped single layer MoS2 based p-n junctions

    [Abstract] [BibTeX]

    		 2013 Applied Physics Letters
    Vol. 102(9), 093104     		 DOI  
    Abstract: The single layer MoS2 is attractive for the use in the next-generation low power nanoelectronic devices because of its intrinsic bandgap compared to graphene. In this work, we investigated the transport property of a p-n junction based on two-dimensional MoS2. The n-type and p-type doping are realized through substituting sulfur with chlorine and phosphorus. The device exhibited backward diode-like behavior with large rectifying ratios. We attribute the observed current-voltage characteristics to different heavy doping effect caused by chlorine and phosphorus. Our results may throw light on the electronic modulation of MoS2 and realizations of complemented logics devices based on MoS2.
    Keywords: ATK; Application; MoS2; p-n junction; diodes; energy gap; molybdenum compounds; rectification; transistors; graphene
    Area: graphene
    BibTeX: 
    @article{Sun2013,
  author = {Sun, Qing-Qing and Li, Yong-Jun and He, Jin-Lan and Yang, Wen and Zhou, Peng and Lu, Hong-Liang and Ding, Shi-Jing and Zhang, David Wei},
  title = {The physics and backward diode behavior of heavily doped single layer MoS2 based p-n junctions},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2013},
  volume = {102},
  number = {9},
  pages = {093104},
  doi = {http://dx.doi.org/10.1063/1.4794802}
}
    Fang Wang, Yonglai Zhang, Yang Liu, Xuefeng Wang, Mingrong Shen, Shuit-Tong Lee & Zhenhui Kang Opto-electronic conversion logic behaviour through dynamic modulation of electron/energy transfer states at the TiO2-carbon quantum dot interface

    [Abstract] [BibTeX]

    		 2013 Nanoscale
    Vol. 5(5), 1831-1835     		 DOI  
    Abstract: Here we show a bias-mediated electron/energy transfer process at the CQDs-TiO2 interface for the dynamic modulation of opto-electronic properties. Different energy and electron transfer states have been observed in the CQDs-TNTs system due to the up-conversion photoluminescence and the electron donation/acceptance properties of the CQDs decorated on TNTs.
    Keywords: ATK; Application; TiO2 nanotube; phonons; photoluminescence; optoelectronics; doping; visible-light; carbon; photocatalyst; nanotubes; circuits
    Area: nanotubes
    BibTeX: 
    @article{Wang2013,
  author = {Wang, Fang and Zhang, Yonglai and Liu, Yang and Wang, Xuefeng and Shen, Mingrong and Lee, Shuit-Tong and Kang, Zhenhui},
  title = {Opto-electronic conversion logic behaviour through dynamic modulation of electron/energy transfer states at the TiO2-carbon quantum dot interface},
  journal = {Nanoscale},
  publisher = {The Royal Society of Chemistry},
  year = {2013},
  volume = {5},
  number = {5},
  pages = {1831--1835},
  doi = {http://dx.doi.org/10.1039/C3NR33985H}
}
    H.P. Xiao, Chaoyu He, C.X. Zhang, L.Z. Sun, Pan Zhou & Jianxin Zhong Stability, electronic structures and transport properties of armchair (10, 10) BN/C nanotubes

    [Abstract] [BibTeX]

    		 2013 Journal of Solid State Chemistry
    Vol. 200(0), 294-298     		 DOI URL 
    Abstract: Using the first-principle calculations, the stability and electronic properties of two novel types of four-segment armchair (10, 10) BN/C hybrid nanotubes ((BN)5C5(BN)5C5NT and (BN)5C5(NB)5C5NT) as well as two-segment armchair (10, 10) BN/C hybrid nanotubes ( ( BN 20-n C n NTs ) are systematically investigated. When n increases from 1 to 4, the band gap of ( BN ) 20-n C n NTs gradually decreases to a narrow one. When 4<=n<=17 , the electronic structure of carbon segment in ( BN ) 20-n C n NTs behaves as zigzag graphene nanoribbons whose band gap is modulated by an inherent electric field of the BN segment. ZGNR-like segments in (BN)5C5(BN)5C5NT and (BN)5C5(NB)5C5NT behave as narrow gap semiconductor and metal, respectively, due to their different chemical environment. Moreover, the (BN)5C5(NB)5C5NT can separate electron and hole carriers, indicating its potential application in solar cell materials. Obvious transport enhancement around the Fermi level is found in the four-segment nanotubes, especially a 6G0 transmission peak in the metallic (BN)5C5(NB)5C5NT.
    Keywords: ATK; Application; boron nitride carbon hybrid nanotubes; density functional theory; non-equilibrium Green's function; electronic properties; transport properties
    Area: nanotubes
    BibTeX: 
    @article{Xiao2013,
  author = {Xiao, H.P. and He, Chaoyu and Zhang, C.X. and Sun, L.Z. and Zhou, Pan and Zhong, Jianxin},
  title = {Stability, electronic structures and transport properties of armchair (10, 10) BN/C nanotubes},
  journal = {Journal of Solid State Chemistry},
  year = {2013},
  volume = {200},
  number = {0},
  pages = {294--298},
  url = {http://www.sciencedirect.com/science/article/pii/S002245961300042X},
  doi = {http://dx.doi.org/10.1016/j.jssc.2013.01.026}
}
    Peng Zhao, De-Sheng Liu, Hai-Ying Liu, Shu-Juan Li & Gang Chen Low bias negative differential resistance in C60 dimer modulated by gate voltage

    [Abstract] [BibTeX]

    		 2013 Organic Electronics
    Vol. 14(4), 1109-1115     		 DOI URL 
    Abstract: By using a combined method of density functional theory and nonequilibrium Green's function formalism, we investigate the electronic transport properties of a gated C60 dimer molecule sandwiched between two gold electrodes. The results show that the gate voltage can strongly affect the electronic transport properties of the C60 dimer and change it from semiconducting to metallic. Negative differential resistance behaviors are obtained in such systems and can be modulated to occur at much lower bias by the gate voltage. The low bias negative differential resistance is analyzed from the calculated transmission spectra, projected density of states and the spatial distribution of molecular projected self-consistent Hamiltonian orbitals along with the voltage drop. These results provide a theoretical support to the design of low bias negative differential resistance molecular device by using the modulation of gate voltage.
    Keywords: ATK; Application; fullerene; electronic transport; negative differential resistance; NDR;
    Area: molecular electronics; fullerenes
    BibTeX: 
    @article{Zhao2013a,
  author = {Zhao, Peng and Liu, De-Sheng and Liu, Hai-Ying and Li, Shu-Juan and Chen, Gang},
  title = {Low bias negative differential resistance in C60 dimer modulated by gate voltage},
  journal = {Organic Electronics},
  year = {2013},
  volume = {14},
  number = {4},
  pages = {1109--1115},
  url = {http://www.sciencedirect.com/science/article/pii/S1566119913000529},
  doi = {http://dx.doi.org/10.1016/j.orgel.2013.01.034}
}
    Jiaping Fan, Nahashon Ndegwa Gathitu, Yingfei Chang & Jingping Zhang Effect of length on the position of negative differential resistance and realization of multifunction in fused oligothiophenes based molecular device

    [Abstract] [BibTeX]

    		 2013 The Journal of Chemical Physics
    Vol. 138(7), 074307     		 DOI  
    Abstract: The length modulation of electron transport properties for molecular devices based on fused oligothiophenes has been investigated theoretically using a combination of non-equilibrium Green's functions and first-principles density functional theory. The results show that the lengths of the molecules have a distinct influence on the position of negative differential resistance (NDR) of the molecular devices. By exploring the effect on transmission properties of substituent groups, hexathieno[3,2-b:2',3'-d]thiophene with -NH2 and -NO2 substituents (model L) can be regard as a good candidate of multifunctional molecular device, which shows excellent rectifying performance (the largest rectification ration is 14.3 at 1.2 V) and clear NDR behavior (at 1.4 V).
    Keywords: ATK; Application; electric properties; Green's function methods; molecular electronics; nanoelectronics; nitrogen compounds; organic compounds; ab-initio; 1st-principles; conductance; contact; transport; junction
    Area: molecular electronics
    BibTeX: 
    @article{Fan2013,
  author = {Fan, Jiaping and Gathitu, Nahashon Ndegwa and Chang, Yingfei and Zhang, Jingping},
  title = {Effect of length on the position of negative differential resistance and realization of multifunction in fused oligothiophenes based molecular device},
  journal = {The Journal of Chemical Physics},
  publisher = {AIP},
  year = {2013},
  volume = {138},
  number = {7},
  pages = {074307},
  doi = {http://dx.doi.org/10.1063/1.4790805}
}
    Zhi-Qiang Fan, Zhen-Hua Zhang, Xiao-Qing Deng, Gui-Ping Tang & Ke-Qiu Chen Controllable low-bias negative differential resistance and rectifying behaviors induced by symmetry breaking

    [Abstract] [BibTeX]

    		 2013 Applied Physics Letters
    Vol. 102(2), 023508     		 DOI  
    Abstract: Incorporating the characteristic of pyramidal electrode and symmetry breaking of molecular structure, we theoretically design a molecular device to perform negative differential resistance and rectifying behaviors simultaneously. The calculated results reveal that low-bias negative differential resistance behaviors can appear symmetrically when tetraphenyl molecule connects to pyramidal gold electrodes. However, as one phenyl of tetraphenyl molecule is replaced by a pyrimidyl, the symmetry breaking on the molecule will break the symmetry of negative differential resistance behavior. The peak-to-valley ratio on negative bias region is larger than that on positive bias region to perform a low-bias rectifying behavior. More importantly, increasing the symmetry breaking can further weaken these two behaviors which propose an effective way to modulate them.
    Keywords: ATK; Application; gold; metal-insulator boundaries; molecular electronics; negative resistance; organic compounds; rectification; molecular rectifiers; atomic-scale device; junction; diode
    Area: molecular electronics
    BibTeX: 
    @article{Fan2013a,
  author = {Fan, Zhi-Qiang and Zhang, Zhen-Hua and Deng, Xiao-Qing and Tang, Gui-Ping and Chen, Ke-Qiu},
  title = {Controllable low-bias negative differential resistance and rectifying behaviors induced by symmetry breaking},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2013},
  volume = {102},
  number = {2},
  pages = {023508},
  doi = {http://dx.doi.org/10.1063/1.4788691}
}
    Afif Gouissem, Wu Fan, Adri C.T. van Duin & Pradeep Sharma A reactive force-field for Zirconium and Hafnium Di-Boride

    [Abstract] [BibTeX]

    		 2013 Computational Materials Science
    Vol. 70(0), 171-177     		 DOI URL 
    Abstract: Zirconium and Hafnium Di-Boride are the two major material systems that are of critical importance for applications in ultra-high temperature environments where both oxidation and mechanical damage mechanisms (such as creep) are operative. Atomistic simulations of these materials at finite temperatures have been hampered due to the unavailability of inter-atomic potentials for the involved elements. In this paper, we present the development of interatomic potentials for both ZrB2 and HfB2 within the ReaxFF framework, thus enabling modeling of chemical reactions. The parameters of the reactive force field are derived by fitting to detailed quantum mechanical simulations of ZrB2 and HfB2 clusters and crystal structures.
    Keywords: ATK; Application; interatomic force-field; chemical reactions; high temperature materials; reaxFF; fitting
    Area: semi
    BibTeX: 
    @article{Gouissem2013,
  author = {Gouissem, Afif and Fan, Wu and van Duin, Adri C.T. and Sharma, Pradeep},
  title = {A reactive force-field for Zirconium and Hafnium Di-Boride},
  journal = {Computational Materials Science},
  year = {2013},
  volume = {70},
  number = {0},
  pages = {171--177},
  url = {http://www.sciencedirect.com/science/article/pii/S0927025613000025},
  doi = {j.commatsci.2012.12.038}
}
    Jing Huang, Qunxiang Li & Jinlong Yang Tuning the Electronic Properties of N@C60 Molecule: A Theoretical Study

    [Abstract] [BibTeX]

    		 2013 Journal of Nanoscience and Nanotechnology
    Vol. 13(2), 1053-1058     		 DOI  
    Abstract: We used first-principle calculations to explore the electronic and transport properties of N@C60 molecule. The calculated results indicate that the N atom locates at either slight or significant off-center in C60 cage under various different chemical environments. The localized N atomic magnetic moment in N@C60 molecule is about 3.0 muB, which is not sensitive to the chemical environment, such as the carrier doping, the external electric field, and the molecule-substrate interaction. On the other hand, the magnetism of N@C60 can be effectively tuned by carrier doping and the cage chemical modification. The C60 cage with delocalized pi-electrons character demonstrates a significant shielding (about 80%) of the encapsulated N atom from the applied external electric field. We do not observe obvious transmission spin polarization in N@C60 molecular junctions and the transmission spectra of two spin channels are similar near the Fermi level.
    Keywords: ATK; Application; molecular electronics; fullerenes
    Area: molecular electronics; fullerenes
    BibTeX: 
    @article{Huang2013,
  author = {Huang, Jing and Li, Qunxiang and Yang, Jinlong},
  title = {Tuning the Electronic Properties of N@C60 Molecule: A Theoretical Study},
  journal = {Journal of Nanoscience and Nanotechnology},
  year = {2013},
  volume = {13},
  number = {2},
  pages = {1053--1058},
  doi = {http://dx.doi.org/10.1166/jnn.2013.6116}
}
    Anurag Srivastava, B. Santhibhushan & Pankaj Dobwal Performance analysis of impurity added benzene based single-electron transistor

    [Abstract] [BibTeX]

    		 2013 Appl. Nanosci.
    Vol. 2Applied Nanoscience, 1-7     		 DOI  
    Abstract: We have analyzed the impurity added benzene based single-electron transistor (SET) using the ab initio approach, based on density functional theory and non-equilibrium Green's function. Boron and nitrogen has been added as impurities either by replacing the last carbon atom or last hydrogen in the benzene. The system has been modeled in such a way that the impurity added benzene is placed above the gate dielectric in coulomb blockade regime between source and drain electrodes for weak coupling. The charging energies of the system have been calculated and discussed in both the isolated as well as SET environments. The conductance dependence of SET on bias potential and gate voltage has been verified through charge stability diagrams.
    Keywords: ATK; Application; impurity added benzene (IAB); single-electron transistor (SET); Charge states, Charging energy, Charge stability diagram
    Area: SET
    BibTeX: 
    @article{Srivastava2013,
  author = {Srivastava, Anurag and Santhibhushan, B. and Dobwal, Pankaj},
  title = {Performance analysis of impurity added benzene based single-electron transistor},
  booktitle = {Applied Nanoscience},
  journal = {Appl. Nanosci.},
  publisher = {Springer-Verlag},
  year = {2013},
  volume = {2},
  pages = {1-7},
  doi = {http://dx.doi.org/10.1007/s13204-013-0194-0}
}
    F. Tavazza, S. Barzilai, D.T. Smith & L.E. Levine The increase in conductance of a gold single atom chain during elastic elongation

    [Abstract] [BibTeX]

    		 2013 Journal of Applied Physics
    Vol. 113(5), 054316     		 DOI  
    Abstract: The conductance of monoatomic gold wires has been studied using ab initio calculations and the transmission was found to vary with the elastic strain. Counter-intuitively, the conductance was found to increase for the initial stages of the elongation, where the structure has a zigzag shape and the bond angles increase from 140° toward 160°. After a certain elongation limit, where the angles are relatively high, the bond length elongation associated with a Peierls distortion reverses this trend and the conductance decreases. These simulations are in good agreement with previously unexplained experimental results.
    Keywords: ATK; Application; nanowire; conductance quantization; elastic properties; plasticity; ab initio calculations; bond angles; bond lengths; elasticity, electrical conductivity; elongation; gold; geometry optimization; transport; molecules; geometry optimization; transport; molecules
    Area: nanowires
    BibTeX: 
    @article{Tavazza2013,
  author = {Tavazza, F. and Barzilai, S. and Smith, D. T. and Levine, L. E.},
  title = {The increase in conductance of a gold single atom chain during elastic elongation},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2013},
  volume = {113},
  number = {5},
  pages = {054316},
  doi = {http://dx.doi.org/10.1063/1.4790379}
}
    Jiaxin Zheng, Lu Wang, Ruge Quhe, Qihang Liu, Hong Li, Dapeng Yu, Wai-Ning Mei, Junjie Shi, Zhengxiang Gao & Jing Lu Sub-10 nm Gate Length Graphene Transistors: Operating at Terahertz Frequencies with Current Saturation

    [Abstract] [BibTeX]

    		 2013 Sci. Rep.
    Vol. 3, 1314     		 DOI URL 
    Abstract: Radio-frequency application of graphene transistors is attracting much recent attention due to the high carrier mobility of graphene. The measured intrinsic cut-off frequency (fT) of graphene transistor generally increases with the reduced gate length (Lgate) till Lgate = 40 nm, and the maximum measured fT has reached 300 GHz. Using ab initio quantum transport simulation, we reveal for the first time that fT of a graphene transistor still increases with the reduced Lgate when Lgate scales down to a few nm and reaches astonishing a few tens of THz. We observe a clear drain current saturation when a band gap is opened in graphene, with the maximum intrinsic voltage gain increased by a factor of 20. Our simulation strongly suggests it is possible to design a graphene transistor with an extraordinary high fT and drain current saturation by continuously shortening Lgate and opening a band gap.
    Keywords: ATK; Application; graphene; scaling laws; applied physics; electronic properties and devices; nanosensors; radio frequency applications; field-effect transistors; walled carbon nanotubes; epitaxial graphene; bilayer graphene; room-temperature; tunable bandgap; boron-nitride; ab-initio; transport; devices
    Area: graphene
    BibTeX: 
    @article{Zheng2013a,
  author = {Zheng, Jiaxin and Wang, Lu and Quhe, Ruge and Liu, Qihang and Li, Hong and Yu, Dapeng and Mei, Wai-Ning and Shi, Junjie and Gao, Zhengxiang and Lu, Jing},
  title = {Sub-10 nm Gate Length Graphene Transistors: Operating at Terahertz Frequencies with Current Saturation},
  journal = {Sci. Rep.},
  publisher = {Macmillan Publishers Limited. All rights reserved},
  year = {2013},
  volume = {3},
  pages = {1314},
  url = {http://dx.doi.org/},
  doi = {http://dx.doi.org/10.1038/srep01314}
}
    Zhaoqiang Bai, Lei Shen, Qingyun Wu, Minggang Zeng, Jian-Sheng Wang, Guchang Han & Yuan Ping Feng Boron diffusion induced symmetry reduction and scattering in CoFeB/MgO/CoFeB magnetic tunnel junctions

    [Abstract] [BibTeX]

    		 2013 Phys. Rev. B
    Vol. 87(1), 014114-     		 DOI  
    Abstract: By first-principles analysis, we investigate the effect of thermal annealing on structural stability of CoFeB/MgO(thin)/CoFeB magnetic tunnel junctions. The calculated phonon dispersion indicates that Mg3B2O6 (kotoite) is a stable spacer after annealing due to B diffusion into MgO. The calculated tunneling magnetoresistance (TMR) of CoFe/kotoite/CoFe is 210%, which is in good agreement with the available experimental value and 2 orders of magnitude lower than the predicted values of CoFe/MgO/CoFe junctions. The physics of this more realistic TMR value is the change in symmetry from C4v of MgO to C2v of kotoite. Such symmetry reduction induces scattering and weakens the tunneling transmission of the &Delta;1-like Bloch states. Our calculations also reveal that the tunneling transmission is sensitive to the electrode/spacer interfacial chemical bonding. Residual boron, localized at the interface due to insufficient annealing temperature, can further reduce the TMR.
    Keywords: ATK; Application; magnetic tunnel junction; spin; MTJ; diffusion; boron; room-temperature; magnetoresistance
    Area: interfaces; spin; semi; nvm
    BibTeX: 
    @article{Bai2013,
  author = {Bai, Zhaoqiang and Shen, Lei and Wu, Qingyun and Zeng, Minggang and Wang, Jian-Sheng and Han, Guchang and Feng, Yuan Ping},
  title = {Boron diffusion induced symmetry reduction and scattering in CoFeB/MgO/CoFeB magnetic tunnel junctions},
  journal = {Phys. Rev. B},
  publisher = {American Physical Society},
  year = {2013},
  volume = {87},
  number = {1},
  pages = {014114--},
  doi = {http://dx.doi.org/10.1103/PhysRevB.87.014114}
}
    Satyendra Singh Chauhan, Pankaj Srivastava & A.K. Shrivastava Effect of Vacancy on Electronic and Transport Properties of Graphene Nanoribbons: An Ab Initio Approach

    [Abstract] [BibTeX]

    		 2012 Journal of Computational and Theoretical Nanoscience
    Vol. 9(12), 2215-2216     		 DOI  
    Abstract: We report a spin-unpolarized density functional theory study of electronic and transport properties of zigzag graphene nanoribbons (ZGNRs) defected with one and two vacancy atoms. The pristine and vacancy defected structures of 8 ZGNRs are found to be metallic. The one atom vacancy ZGNRs is energetically more stable. The localized states appear when there are vacancies inside the ZGNRs, which affects its transmission. In case of two vacancies in the ZGNRs the additional peak in DOS is observed close to the Fermi level and the transmission decreases further. Hence, our results point towards the relative suitability of these materials in nanoelectronics applications.
    Keywords: ATK; Application; graphene nanoribbons; stability; electronic; transport; metallic; defect
    Area: graphene
    BibTeX: 
    @article{Chauhan2012a,
  author = {Chauhan, Satyendra Singh and Srivastava, Pankaj and Shrivastava, A.K.},
  title = {Effect of Vacancy on Electronic and Transport Properties of Graphene Nanoribbons: An Ab Initio Approach},
  journal = {Journal of Computational and Theoretical Nanoscience},
  year = {2012},
  volume = {9},
  number = {12},
  pages = {2215--2216},
  doi = {http://dx.doi.org/10.1166/jctn.2012.2641}
}
    Ming-Jun Li, Meng-Qiu Long, Ke-Qiu Chen & Hui Xu Fluorination effects on the electronic transport properties of dithiophene-tetrathiafulvalene (DT-TTF) molecular junctions

    [Abstract] [BibTeX]

    		 2013 Solid State Communications
    Vol. 157(0), 62-67     		 DOI URL 
    Abstract: The fluorination of dithiophene-tetrathiafulvalent (DT-TTF) was investigated by using the density functional theory combined with nonequilibrium Green's function method. It is demonstrated that fluorination can modify the electronic transport properties of DT-TTF. Negative differential resistance can be observed within a certain bias voltage range in 4FDT-TTF.
    Keywords: ATK; Application; molecular electronics; dithiophene-tetrathiafulvalene; fluorination effect; transport property; NDR behavior; negative differential resistance; field-effect transistors; intermolecular interaction; high-performance; high-mobility; metal-ions; ab-initio; devices; 1st-principles; wires
    Area: molecular electronics
    BibTeX: 
    @article{Li2013,
  author = {Li, Ming-Jun and Long, Meng-Qiu and Chen, Ke-Qiu and Xu, Hui},
  title = {Fluorination effects on the electronic transport properties of dithiophene-tetrathiafulvalene (DT-TTF) molecular junctions},
  journal = {Solid State Communications},
  year = {2013},
  volume = {157},
  number = {0},
  pages = {62--67},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109812006539},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.12.001}
}
    Hongmei Liu, Hongbo Wang, Jianwei Zhao & Manabu Kiguchi Molecular rectification in triangularly shaped graphene nanoribbons

    [Abstract] [BibTeX]

    		 2013 J. Comput. Chem.
    Vol. 34(5), 360-365     		 DOI  
    Abstract: We present a theoretical study of electron transport in tailored zigzag graphene nanoribbons (ZGNRs) with triangular structure using density functional theory together with the nonequilibrium Green's function formalism. We find significant rectification with a favorite electron transfer direction from the vertex to the right edge. The triangular ZGNR connecting to the electrode with one thiol group at each terminal shows an average rectification ratio of 8.4 over the bias range from -1.0 to 1.0 V. This asymmetric electron transport property originates from nearly zero band gap of triangular ZGNR under negative bias, whereas a band gap opens under positive bias. When the molecule is connected to the electrode by multithiol groups, the current is enhanced due to strong interfacial coupling; however, the rectification ratio decreases. The simulation results indicate that the unique electronic states of triangular ZGNR are responsible for rectification, rather than the asymmetric anchoring groups.
    Keywords: ATK; Application; triangular graphene nanoribbon; molecular rectification; band gap; electron transport; quantum-interference; electron-transport; wire junctions; conductance; resistance; nanodisk; contact; formula
    Area: graphene
    BibTeX: 
    @article{Liu2013,
  author = {Liu, Hongmei and Wang, Hongbo and Zhao, Jianwei and Kiguchi, Manabu},
  title = {Molecular rectification in triangularly shaped graphene nanoribbons},
  journal = {J. Comput. Chem.},
  publisher = {Wiley Subscription Services, Inc., A Wiley Company},
  year = {2013},
  volume = {34},
  number = {5},
  pages = {360--365},
  doi = {http://dx.doi.org/10.1002/jcc.23142}
}
    M. Qiu & K.M. Liew Length dependence of carbon-doped BN nanowires: A-D Rectification and a route to potential molecular devices

    [Abstract] [BibTeX]

    		 2013 Journal of Applied Physics
    Vol. 113(5), 054305     		 DOI  
    Abstract: Based on the first-principles approach, electronic transport properties of different lengths of carbon-doped boron-nitrogen nanowires, capped with two thiols as end groups connected to Au electrodes surfaces, are investigated. The results show that rectifying performance and negative differential resistance (NDR) behaviors can be enhanced obviously by increasing the length. Analysis of Mülliken population, transmission spectra, evolutions of frontier orbitals and molecular projected self-consistent Hamiltonian of molecular orbital indicate that electronic transmission strength, charge transfer and distributions of molecular states change are the intrinsic origin of these rectifying performances and NDR behaviors.
    Keywords: ATK; Application; wide band gap semiconductors; boron-nitride; doping; negative differential resistance; NDR
    Area: molecular electronics; nanowires
    BibTeX: 
    @article{Qiu2013,
  author = {Qiu, M. and Liew, K. M.},
  title = {Length dependence of carbon-doped BN nanowires: A-D Rectification and a route to potential molecular devices},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2013},
  volume = {113},
  number = {5},
  pages = {054305},
  doi = {http://dx.doi.org/10.1063/1.4790306}
}
    Hari Mohan Rai, Neeraj K. Jaiswal, Pankaj Srivastava & Rajnish Kurchania Electronic and Transport Properties of Zigzag Boron Nitride Nanoribbons

    [Abstract] [BibTeX]

    		 2013 Journal of Computational and Theoretical Nanoscience
    Vol. 10(2), 368-375     		 DOI  
    Abstract: We have systematically investigated the electronic and transport properties of bare and hydrogenated zigzag boron nitride nanoribbons (ZBNNRs). We employed the spin unrestricted density functional theory (DFT) calculations within the local spin density approximation (LSDA) to reveal the semi-metallicity in bare ZBNNRs. Both-edges H-termination turns the ribbons semiconducting. Moreover, the band gap of both-edges H-terminated ZBNNRs is inversely proportional to the ribbon width. Interestingly, only boron edge H-passivated ZBNNRs leads to semi-metallic character whereas only nitrogen edge H-termination exhibits semiconducting behavior. The breaking of degeneracy for up spin and down spin electrons, as observed in bare and one edge H-terminated ZBNNRs points towards the possibility of spin polarized current. The transmission spectrum (TS) analysis also confirms the separation of spin up and down electrons making ZBNNR a suitable candidate for spin filter devices and other spintronics applications.
    Keywords: ATK; Application; boron nitride nanoribbons; spin; band structures; density of states; transmission spectra
    Area: graphene; spin
    BibTeX: 
    @article{Rai2013,
  author = {Rai, Hari Mohan and Jaiswal, Neeraj K. and Srivastava, Pankaj and Kurchania, Rajnish},
  title = {Electronic and Transport Properties of Zigzag Boron Nitride Nanoribbons},
  journal = {Journal of Computational and Theoretical Nanoscience},
  year = {2013},
  volume = {10},
  number = {2},
  pages = {368--375},
  doi = {http://dx.doi.org/10.1166/jctn.2013.2706}
}
    S Barzilai, F Tavazza & L E Levine The effect of internal impurities on the mechanical and conductance properties of gold nanowires during elongation

    [Abstract] [BibTeX]

    		 2013 Modelling and Simulation in Materials Science and Engineering
    Vol. 21(2), 025004-     		 DOI URL 
    Abstract: The conductance and mechanical properties of contaminated gold nanowires (NWs) were studied using first principle calculations. Nanowires containing internal impurities of H 2 O or O 2 were elongated along two different directions. It was found that both impurities interact with the gold atoms and affect the properties of the NWs. From a mechanical viewpoint, the impurities increase the bond strength in their vicinity and, throughout the entire elongation, remain surrounded by gold atoms. The impurities do not migrate to the surface and never end up in the single atom chain. The NW fracture always occurs at an Au-Au bond, far from the impurity. Therefore, the impurities do not affect the fracture strength but do decrease the strain at fracture. A variety of conductance effects were observed depending on the type and location of the impurity, and the O 2 has the most significant impact. The O 2 reduces the conductance when it is close to the gold atoms in the main pathway. However, at the late stages of the elongation, both impurities are located far from the main pathway and have little influence on the conductance.
    Keywords: ATK; ATK-SE; Application; nanowire; mechanical properties; deformation; plasticity; defects; structural failure; quantum wire; nanowire; atomic wire; nanowire;
    Area: nanowires
    BibTeX: 
    @article{Barzilai2013,
  author = {Barzilai, S and Tavazza, F and Levine, L E},
  title = {The effect of internal impurities on the mechanical and conductance properties of gold nanowires during elongation},
  journal = {Modelling and Simulation in Materials Science and Engineering},
  year = {2013},
  volume = {21},
  number = {2},
  pages = {025004--},
  url = {http://stacks.iop.org/0965-0393/21/i=2/a=025004},
  doi = {http://dx.doi.org/10.1088/0965-0393/21/2/025004}
}
    Yukihito Matsuura Current rectification in nickelocenylferrocene sandwiched between two gold electrodes

    [Abstract] [BibTeX]

    		 2013 J. Chem. Phys.
    Vol. 138(1), 014311-4     		 DOI  
    Abstract: I present a theoretical study of the electronic transport properties of nickelocenylferrocene sandwiched between gold electrodes. Compared with the biferrocene system, the nickelocenylferrocene system had high electrical conduction and rectification in the bias range -1 to 1 V. Furthermore, the spin-down states of the nickelocenylferrocene system exhibited perfect spin-filtering properties. From the electronic states of the nickelocenylferrocene, it was found that the rectification was caused by a difference in the bias-dependent behaviors between the Fe 3d and Ni 3d orbitals.
    Keywords: electrical conductivity, nickel compounds, organic compounds, rectification, ATK, Application, spin
    Area: molecular electronics; spin
    BibTeX: 
    @article{Matsuura2013,
  author = {Matsuura, Yukihito},
  title = {Current rectification in nickelocenylferrocene sandwiched between two gold electrodes},
  journal = {J. Chem. Phys.},
  publisher = {AIP},
  year = {2013},
  volume = {138},
  number = {1},
  pages = {014311--4},
  doi = {http://dx.doi.org/10.1063/1.4773404}
}
    Haiqing Wan, Benhu Zhou, Wenhu Liao & Guanghui Zhou Spin-filtering and rectification effects in a Z-shaped boron nitride nanoribbon junction

    [Abstract] [BibTeX]

    		 2013 The Journal of Chemical Physics
    Vol. 138(3), 034705     		 DOI URL 
    Abstract: A Z-shaped junction constructed by a few-nanometer-long armchair-edged boron nitride nanoribbon (ABNNR) sandwiched between two semi-infinite zigzag-edged BNNR electrodes with different hydrogen-passivated edge treatment is proposed, and its spin-dependent electronic transport is studied by ab initio calculations. It is found that a short ABNNR exhibits metallic behavior and can be used as a conduction channel. Interestingly, the spin-filtering and rectification effects exist in the junctions without any edge passivation or with boron-edge passivation. The analysis on the projected density of states and spatial distribution of molecular projected self-consistent Hamiltonian eigenstates gives an insight into the observed results for the system. Our results suggest that a BNNR-based nanodevices with spin-filtering and rectification effects may be synthesized from an hexagonal boron nitride sheet by properly tailoring and edge passivation.
    Keywords: ATK; Application; ab initio calculations; boron compounds; electrodes; electronic density of states; III-V semiconductors; nanoribbons; passivation; rectification; SCF calculations; wide band gap semiconductors; molecular rectifiers; graphene; transport; edges
    Area: graphene
    BibTeX: 
    @article{Wan2013,
  author = {Haiqing Wan and Benhu Zhou and Wenhu Liao and Guanghui Zhou},
  title = {Spin-filtering and rectification effects in a Z-shaped boron nitride nanoribbon junction},
  journal = {The Journal of Chemical Physics},
  publisher = {AIP},
  year = {2013},
  volume = {138},
  number = {3},
  pages = {034705},
  url = {http://link.aip.org/link/?JCP/138/034705/1},
  doi = {http://dx.doi.org/10.1063/1.4775841}
}
    Neng-Ping Wang & Xiao-Jun Xu Effects of defects near source or drain contacts of carbon nanotube transistors

    [Abstract] [BibTeX]

    		 2012 EPL (Europhysics Letters)
    Vol. 100(4), 47009-     		 DOI URL 
    Abstract: We calculate the amplitude of the random-telegraph-signal (RTS) noise due to a single charged defect in a long-channel p-type carbon nanotube field-effect transistor, using the nonequilibrium Green function method in a tight-binding approximation. We find that the amplitude of the RTS noise caused by a positive charge close to the source (or drain) contact increases with the applied gate voltage and drain voltage. A positive charge located at the nanotube-oxide interface and close to the source (or drain) contact may cause a large RTS noise of about 50% in the on-state.
    Keywords: Application; ATK-SE; field-effect transistors; random-telegraph-signal; low-frequency noise; 1/f noise; fluctuations; interface
    Area: nanotubes
    BibTeX: 
    @article{Wang2012c,
  author = {Wang, Neng-Ping and Xu, Xiao-Jun},
  title = {Effects of defects near source or drain contacts of carbon nanotube transistors},
  journal = {EPL (Europhysics Letters)},
  year = {2012},
  volume = {100},
  number = {4},
  pages = {47009--},
  url = {http://stacks.iop.org/0295-5075/100/i=4/a=47009},
  doi = {http://dx.doi.org/10.1209/0295-5075/100/47009}
}
    Jiaxin Zheng, Chengyong Xu, Lu Wang, Qiye Zheng, Hong Li, Qihang Liu, Ruge Quhe, Zhengxiang Gao, Junjie Shi & Jing Lu Sign-changeable spin-filter efficiency in linear carbon atomic chain

    [Abstract] [BibTeX]

    		 2013 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 48(0), 101-105     		 DOI URL 
    Abstract: It is well known that there is spin-filter efficiency (SFE) of a linear carbon atomic chain. In this article, we examine the quantum transport calculations of a linear carbon atomic chain connected to two half-planar graphene electrodes by using the first-principle method and reveal for the first time that sign of the SFE of such carbon atomic chain is changeable with the bias. This makes the carbon atomic chains attractive to potential application of spintronics.
    Keywords: ATK; Application; graphene; molecular electronics; atomic chain; spin filter;
    Area: molecular electronics; graphene; spin
    BibTeX: 
    @article{Zheng2013,
  author = {Zheng, Jiaxin and Xu, Chengyong and Wang, Lu and Zheng, Qiye and Li, Hong and Liu, Qihang and Quhe, Ruge and Gao, Zhengxiang and Shi, Junjie and Lu, Jing},
  title = {Sign-changeable spin-filter efficiency in linear carbon atomic chain},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2013},
  volume = {48},
  number = {0},
  pages = {101--105},
  url = {http://www.sciencedirect.com/science/article/pii/S1386947712004778},
  doi = {http://dx.doi.org/10.1016/j.physe.2012.12.009}
}
    Satyendra Singh Chauhan, Pankaj Srivastava & A.K. Shrivastava Band gap engineering in doped graphene nanoribbons: An ab initio approach

    [Abstract] [BibTeX]

    		 2013 Solid State Communications
    Vol. 154(0), 69-71     		 DOI URL 
    Abstract: We present first principle study for stability and electronic properties of armchair graphene nanoribbons (AGNRs). We have investigated the stability and electronic properties of armchair graphene nanoribbons whose edges are doped with (i) s-type elements, Mg (ii) p-type elements, B and S, and (iii) 3d-type TMs, Ti and Mn, atoms using density functional theory. We predict that transition metals as substitutional dopant in AGNRs are energetically more favorable and minimize the band gap. The edges of the AGNRs are chemically more active and they can accommodate appropriate dopants to obtain different electronic properties having the same geometrical structure of the ribbon. Our results suggest that such materials can be used for nanoelectronic and spintronic applications.
    Keywords: ATK, Application, graphene nanoribbons, density functional theory, stability, band gap
    Area: graphene
    BibTeX: 
    @article{Chauhan2013,
  author = {Chauhan, Satyendra Singh and Srivastava, Pankaj and Shrivastava, A.K.},
  title = {Band gap engineering in doped graphene nanoribbons: An ab initio approach},
  journal = {Solid State Communications},
  year = {2013},
  volume = {154},
  number = {0},
  pages = {69--71},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109812005832},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.10.030}
}
    Sudhanshu Choudhary & S. Qureshi Theoretical study on the effect of dopant positions and dopant density on transport properties of a BN co-doped SiC nanotube

    [Abstract] [BibTeX]

    		 2013 Physics Letters A
    Vol. 377(5), 430-435     		 DOI URL 
    Abstract: We investigate the effect of dopant (boron 'B' - nitrogen 'N') position and density on electronic transport properties of a BN co-doped silicon carbide nanotube (SiCNT). The results show an increase in conductance when both BN impurities are far in space from each other. Orbital delocalization and appearance of new electronic states around Fermi level contribute to the current when this spacing is increased. On the other hand, a reduction in SiCNT conductivity was observed when BN dopant density was increased. This is attributed to the electronic states moving away from the Fermi level and orbital localization at higher bias voltages.
    Keywords: ATK; Application; ab initio; DFT; NEGF; SiCNT; nanotubes; doping; silicon-carbide nanotubes; electron-transport
    Area: nanotubes
    BibTeX: 
    @article{Choudhary2013,
  author = {Choudhary, Sudhanshu and Qureshi, S.},
  title = {Theoretical study on the effect of dopant positions and dopant density on transport properties of a BN co-doped SiC nanotube},
  journal = {Physics Letters A},
  year = {2013},
  volume = {377},
  number = {5},
  pages = {430--435},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960112012753},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.12.007}
}
    X.J. Tan, H.J. Liu, J. Wei, J. Shi, X.F. Tang & C. Uher Thermoelectric properties of small diameter carbon nanowires

    [Abstract] [BibTeX]

    		 2013 Carbon
    Vol. 53(0), 286-291     		 URL 
    Abstract: The room temperature thermoelectric properties of three kinds of small diameter carbon nanowires are investigated by using nonequilibrium Green's function method and molecular dynamics simulations. Due to very low thermal conductance and a relatively high power factor, these nanowires are found to exhibit better thermoelectric performance than other low-dimensional carbon-based materials such as carbon nanotubes. Moreover, the ZT values of these systems can be further increased to about 10 by partial passivation of hydrogen, which greatly reduces both the electron and phonon contributions to the thermal conductance, but leaves the power factor less affected.
    Keywords: ATK; Application; carbon nanowire; thermoelectric properties; ZT; passivation; thermal conductance; nonequilibrium molecular-dynamics; thermal conductivity; nanowires; simulation; nanotubes; figure; merit of performance; metals
    Area: nanowires; thermo
    BibTeX: 
    @article{Tan2013,
  author = {Tan, X.J. and Liu, H.J. and Wei, J. and Shi, J. and Tang, X.F. and Uher, C.},
  title = {Thermoelectric properties of small diameter carbon nanowires},
  journal = {Carbon},
  year = {2013},
  volume = {53},
  number = {0},
  pages = {286--291},
  url = {http://www.sciencedirect.com/science/article/pii/S0008622312008731}
}
    X.Z. Wu, J. Xiao, L.N. Chen, C. Cao, H. Xu & M.Q. Long The effect of asymmetrical electrode on the transport properties of molecular devices

    [Abstract] [BibTeX]

    		 2013 Physica B: Condensed Matter
    Vol. 411(0), 131-135     		 DOI URL 
    Abstract: By applying nonequilibrium Green's functions in combination with the density functional theory, we have investigated the electronic transport properties of molecular devices consisting of the carbon atomic chain coupling with symmetry and asymmetry Au electrodes. The asymmetry Au electrodes systems display good rectifying behavior. The main origin of this phenomenon is that a molecular core coupling with asymmetry electrodes can generate two asymmetrical Schottky barriers at both extended molecule regions. This rectification is also explained by the calculated transmission spectrum and the spatial distribution of the LUMO and HOMO states.
    Keywords: Transport properties, Molecular device, Rectifying behavior, Asymmetry electrode, atomic chain, ATK, Application
    Area: molecular electronics
    BibTeX: 
    @article{Wu2013,
  author = {Wu, X.Z. and Xiao, J. and Chen, L.N. and Cao, C. and Xu, H. and Long, M.Q.},
  title = {The effect of asymmetrical electrode on the transport properties of molecular devices},
  journal = {Physica B: Condensed Matter},
  year = {2013},
  volume = {411},
  number = {0},
  pages = {131--135},
  url = {http://www.sciencedirect.com/science/article/pii/S0921452612010241},
  doi = {http://dx.doi.org/10.1016/j.physb.2012.11.028}
}
    Penchalaiah Palla & J.P. Raina Effect of Hexagonal Boron Nitride on Energy Band Gap of Graphene Antidot Structures

    [Abstract] [BibTeX]

    		 2012 Innovative Systems Design and Engineering
    Vol. 3(12), 27-39     		 URL 
    Abstract: The zero band gap (Eg) graphene becomes narrow Eg semiconductor when graphene is patterned with periodic array of hexagonal shaped antidots, the resultant is the hexagonal Graphene Antidot Lattice (hGAL). Based on the number of atomic chains between antidots, hGALs can be even and odd. The even hGALs (ehGAL) are narrow Eg semiconductors and odd hGALs (ohGAL) are semi-metals. The Eg opening up by hGALs is not sufficient to operate a realistic switching transistor. Also hGAL transistors realized on Si/SiO2 substrate are suffering with low carrier mobility and ON-OFF current ratio. In order to achieve a sizable Eg with good mobility, AB Bernal stacked hGALs on hexagonal Boron Nitride (hBN), ABA Bernal stacked hBN / hGAL / hBN sandwiched structures and AB misaligned hGAL /hBN structures are reported here for the first time. Using the first principles method the electronic structure calculations are performed. A sizable Eg of about 1.04 eV (940+100 meV ) is opened when smallest neck width medium radius ehGAL supported on hBN and about 1.1 eV (940 + 200 meV ) is opened when the same is sandwiched between hBN layers. A band gap on the order of 71 meV is opened for Bernal stacked ohGAL / hBN and nearly 142 meV opened for hBN / ohGAL /hBN structures for smallest radius and width of nine atomic chains between antidots. Unlike a misaligned graphene on hBN, the misaligned ohGAL/hBN structure shows increased Eg. This study could open up new ways of band gap engineering for graphene based nanostructures.
    Keywords: ATK-SE, ATK, Application, Graphene, graphene antidots, hexagonal boron nitride, band structure, band gap engineering
    Area: graphene
    BibTeX: 
    @article{Palla2012,
  author = {Penchalaiah Palla and J.P. Raina},
  title = {Effect of Hexagonal Boron Nitride on Energy Band Gap of Graphene Antidot Structures},
  journal = {Innovative Systems Design and Engineering},
  year = {2012},
  volume = {3},
  number = {12},
  pages = {27-39},
  url = {http://www.iiste.org/Journals/index.php/ISDE/article/view/3653}
}
    Zhi-Qiang Fan, Zhen-Hua Zhang, Xiao-Qing Deng, Gui-Ping Tang & Ke-Qiu Chen Reversible switching in an N-salicylideneaniline molecular device induced by hydrogen transfer

    [Abstract] [BibTeX]

    		 2012 Organic Electronics
    Vol. 13(12), 2954-2958     		 DOI URL 
    Abstract: By applying nonequilibrium Green's functions in combination with the density-functional theory, we investigate the electronic transport properties of an N-salicylideneaniline molecule sandwiched between two Au electrodes. The results show that the currents between the enol and keto tautomeric forms of the molecule vary widely and a reversible switching behavior can be found in this device due to the photoinduced hydrogen transfer. In addition, the current switching ratio which is a typical character of switching behavior will lower a little when an electron-donating group (-NH2) substitutes the right end hydrogen atom of the N-salicylideneaniline molecule. However, the substituent of an electron-withdrawing group (-NO2) on the same site can enlarge the current switching ratio two orders of magnitude, which greatly improve the potential of the N-salicylideneaniline molecular device in future logic and memory.
    Keywords: Molecular device, Electronic transport, Switching behavior, ATK, Application
    Area: molecular electronics
    BibTeX: 
    @article{Fan2012c,
  author = {Fan, Zhi-Qiang and Zhang, Zhen-Hua and Deng, Xiao-Qing and Tang, Gui-Ping and Chen, Ke-Qiu},
  title = {Reversible switching in an N-salicylideneaniline molecular device induced by hydrogen transfer},
  journal = {Organic Electronics},
  year = {2012},
  volume = {13},
  number = {12},
  pages = {2954--2958},
  url = {http://www.sciencedirect.com/science/article/pii/S1566119912003928},
  doi = {http://dx.doi.org/10.1016/j.orgel.2012.08.019}
}
    Mausumi Chattopadhyaya, Md. Mehboob Alam, Sabyasachi Sen & Swapan Chakrabarti Electrostatic Spin Crossover and Concomitant Electrically Operated Spin Switch Action in a Ti-Based Endohedral Metallofullerene Polymer

    [Abstract] [BibTeX]

    		 2012 Phys. Rev. Lett.
    Vol. 109(25), 257204-     		 DOI  
    Abstract: Herein, we predict that a 1D chain of Ti@C32-C2-Ti@C32 (TEMF) will act as a spin switch in the presence of an electric field. The spin resolved density of states analyses reveal that, surprisingly, both the low- and high-spin states of TEMF are half-metal; however, the metallic density of states comes from the opposite spin channels of the two spin states. More remarkably, it is found that the electric field driven spin crossover between the low and high state in TEMF is achievable at field strength 1.04 V/nm, which eventually leads to the realization of the first ever electrically operated spin switch device.
    Keywords: ATK; Application; molecular electronics; atomic chain; spin switch; fullerenes
    Area: molecular electronics; fullerenes; spin
    BibTeX: 
    @article{Chattopadhyaya2012,
  author = {Chattopadhyaya, Mausumi and Alam, Md. Mehboob and Sen, Sabyasachi and Chakrabarti, Swapan},
  title = {Electrostatic Spin Crossover and Concomitant Electrically Operated Spin Switch Action in a Ti-Based Endohedral Metallofullerene Polymer},
  journal = {Phys. Rev. Lett.},
  publisher = {American Physical Society},
  year = {2012},
  volume = {109},
  number = {25},
  pages = {257204--},
  doi = {http://dx.doi.org/10.1103/PhysRevLett.109.257204}
}
    R.K. Ghosh, S. Bhattacharya & S. Mahapatra Physics-Based Band Gap Model for Relaxed and Strained [100] Silicon Nanowires

    [Abstract] [BibTeX]

    		 2012 Electron Devices, IEEE Transactions on
    Vol. 59(6)Electron Devices, IEEE Transactions on, 1765-1772     		 DOI  
    Abstract: In this paper, we propose a physics-based simplified analytical model of the energy band gap and electron effective mass in a relaxed and strained rectangular [100] silicon nanowires (SiNWs). Our proposed formulation is based on the effective mass approximation for the nondegenerate two-band model and 4 x 4 Lüttinger Hamiltonian for energy dispersion relation of conduction band electrons and the valence band heavy and light holes, respectively. Using this, we demonstrate the effect of the uniaxial strain applied along [100]-direction and a biaxial strain, which is assumed to be decomposed from a hydrostatic deformation along [001] followed by a uniaxial one along the [100]-direction, respectively, on both the band gap and the transport and subband electron effective masses in SiNW. Our analytical model is in good agreement with the extracted data using the extended-Hückel-method-based numerical simulations over a wide range of device dimensions and applied strain.
    Keywords: ATK-SE, Application, Analytical models, Dispersion, Effective mass, Photonic band gap, Silicon, Strain, Wires, deformation, electrons, elemental semiconductors, hydrostatics, nanowires, numerical analysis, silicon, Lüttinger Hamiltonian, Si, biaxial strain, conduction band electron, effective mass approximation, electron effective mass, energy band gap, energy dispersion relation, extended-Hückel-method-based numerical simulation, hydrostatic deformation, nondegenerate two-band model, physics-based band gap model, physics-based simplified analytical model, relaxed nanowire, strained nanowire, uniaxial strain effect, valence band heavy hole, valence band light hole, Band gap, effective mass, nanowires, size quantization, strain
    Area: semi
    BibTeX: 
    @article{Ghosh2012,
  author = {Ghosh, R.K. and Bhattacharya, S. and Mahapatra, S.},
  title = {Physics-Based Band Gap Model for Relaxed and Strained [100] Silicon Nanowires},
  booktitle = {Electron Devices, IEEE Transactions on},
  journal = {Electron Devices, IEEE Transactions on},
  year = {2012},
  volume = {59},
  number = {6},
  pages = {1765--1772},
  doi = {http://dx.doi.org/10.1109/TED.2012.2190737}
}
    Ram Krishna Ghosh, Sitangshu Bhattacharya & Santanu Mahapatra k.p based closed form energy band gap and transport electron effective mass model for [100] and [110] relaxed and strained Silicon nanowire

    [Abstract] [BibTeX]

    		 2013 Solid-State Electronics
    Vol. 80(0), 124-134     		 DOI URL 
    Abstract: In this paper, we address a physics based closed form model for the energy band gap (Eg) and the transport electron effective mass in relaxed and strained [1 0 0] and [1 1 0] oriented rectangular Silicon Nanowire (SiNW). Our proposed analytical model along [1 0 0] and [1 1 0] directions are based on the k.p formalism of the conduction band energy dispersion relation through an appropriate rotation of the Hamiltonian of the electrons in the bulk crystal along [0 0 1] direction followed by the inclusion of a 4 x Lüttinger Hamiltonian for the description of the valance band structure. Using this, we demonstrate the variation in Eg and the transport electron effective mass as function of the cross-sectional dimensions in a relaxed [1 0 0] and [1 1 0] oriented SiNW. The behaviour of these two parameters in [1 0 0] oriented SiNW has further been studied with the inclusion of a uniaxial strain along the transport direction and a biaxial strain, which is assumed to be decomposed from a hydrostatic deformation along [0 0 1] with the former one. In addition, the energy band gap and the effective mass of a strained [1 1 0] oriented SiNW has also been formulated. Using this, we compare our analytical model with that of the extracted data using the nearest neighbour empirical tight binding sp3d5s* method based simulations and has been found to agree well over a wide range of device dimensions and applied strain.
    Keywords: Silicon nanowire, Size quantization, Band gap, Effective mass, Strain, ATK-SE, Application
    Area: semi
    BibTeX: 
    @article{Ghosh2013a,
  author = {Ghosh, Ram Krishna and Bhattacharya, Sitangshu and Mahapatra, Santanu},
  title = {k.p based closed form energy band gap and transport electron effective mass model for [100] and [110] relaxed and strained Silicon nanowire},
  journal = {Solid-State Electronics},
  year = {2013},
  volume = {80},
  number = {0},
  pages = {124--134},
  url = {http://www.sciencedirect.com/science/article/pii/S0038110112003516},
  doi = {http://dx.doi.org/10.1016/j.sse.2012.11.001}
}
    Y. Al & H.L. Zhang Construction and Conductance Measurement of Single Molecule Junctions

    [Abstract] [BibTeX]

    		 2012 Acta Physico-chimica Sinica
    Vol. 28(10), 2237-2248     		 DOI  
    Abstract: Molecular electronics has become an important research field in the past decade, and molecular devices can be used as molecular wires, switches, rectifiers, and transistors etc. Construction of metal/molecule/metal (MMM) junctions is the most effective method for investigating the charge transport properties of molecular devices. However, the measurement of individual molecule junctions at the nanoscale is still very challenging because of many technical difficulties. This paper reviews the recent progress and the challenges in the measurement of single molecule conductance, and summarizes investigation of the charge transport mechanism.
    Keywords: atomic-force microscopy; walled carbon nanotubes; electronic devices; charge-transport; electrical conductance; quantum transport; metal nanowires; break junctions; scanning probe; spin; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Al2012,
  author = {Al, Y. and Zhang, H. L.},
  title = {Construction and Conductance Measurement of Single Molecule Junctions},
  journal = {Acta Physico-chimica Sinica},
  publisher = {Peking Univ Press},
  year = {2012},
  volume = {28},
  number = {10},
  pages = {2237--2248},
  doi = {http://dx.doi.org/10.3866/PKU.WHXB201209102}
}
    Sudhanshu Choudhary & S. Qureshi Effect of moisture on electron transport in SiC nanotubes: An ab-initio study

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(45), 3359-3362     		 DOI URL 
    Abstract: We investigate the effect of moisture-adsorption on the electronic transport properties of a silicon-carbide nanotube (SiCNT). The results obtained by relaxing an H2O (water) molecule over an (8,0 ) SiCNT show that water molecule binds with SiCNT. The formation of SiO bond (bond length 1.95 Å) between the SiCNT and H2O molecule was discovered. However, previous studies on H2O adsorbtion in carbon nanotubes (CNTs) have shown the formation of CH bond at the CNT surface. Current-voltage (I-V) characteristics show a reduction in SiCNT conductivity when the number of H2O molecules over SiCNT were increased.
    Keywords: ATK; Application; sensor; ab-initio; DFT; NEGF; SiCNT; carbon nanotube;
    Area: nanotubes
    BibTeX: 
    @article{Choudhary2012a,
  author = {Choudhary, Sudhanshu and Qureshi, S.},
  title = {Effect of moisture on electron transport in SiC nanotubes: An ab-initio study},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {45},
  pages = {3359--3362},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960112009693},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.08.052}
}
    R.K. Ghosh & S. Mahapatra Direct Band-to-Band Tunneling in Reverse Biased MoS2 Nanoribbon p-n Junctions

    [Abstract] [BibTeX]

    		 2013 IEEE Transactions on Electron Devices
    Vol. 60(1), 274-279     		 DOI  
    Abstract: We investigate the direct band-to-band tunneling (BTBT) in a reverse biased molybdenum disulfide (MoS2) nanoribbon p-n junction by analyzing the complex band structure obtained from semiempirical extended Hückel method under relaxed and strained conditions. It is demonstrated that the direct BTBT is improbable in relaxed monolayer nanoribbon; however, with the application of certain uniaxial tensile strain, the material becomes favorable for it. On the other hand, the relaxed bilayer nanoribbon is suitable for direct BTBT but becomes unfavorable when the applied uniaxial tensile or compressive strain goes beyond a certain limit. Considering the Wentzel-Kramers-Brillouin approximation, we evaluate the tunneling probability to estimate the tunneling current for a small applied reverse bias. Reasonably high tunneling current in the MoS2 nanoribbons shows that it can take advantage over graphene nanoribbon in future tunnel field-effect transistor applications.
    Keywords: ATK-SE, Application, bandgap, band-to-band tunneling (BTBT), complex band structure, nanoribbon, strain, MoS2
    Area: graphene
    BibTeX: 
    @article{Ghosh2013,
  author = {Ghosh, R. K. and Mahapatra, S.},
  title = {Direct Band-to-Band Tunneling in Reverse Biased MoS2 Nanoribbon p-n Junctions},
  journal = {IEEE Transactions on Electron Devices},
  year = {2013},
  volume = {60},
  number = {1},
  pages = {274-279},
  doi = {http://dx.doi.org/10.1109/TED.2012.2226729}
}
    Yan-Dong Guo, Xiao-Hong Yan & Yang Xiao Computational Investigation of DNA Detection Using Single-Electron Transistor-Based Nanopore

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(40)The Journal of Physical Chemistry C, 21609-21614     		 DOI  
    Abstract: We propose a single-electron transistor (SET)-based nanopore sensor for DNA sequencing, which consists of source, drain, and gate electrodes, as well as a nanopore where the DNA molecule is pulled through. For nanopore sensors based on transverse electronic transport, generally, the tunneling current is relatively small due to the weak coupling between the molecule and electrodes. We take full advantage of this feature by introducing SET to make the device operate in Coulomb-blockade regime. Through first-principles simulations, the charge stability diagrams of the nucleobases within the SET-nanopore environment are demonstrated to be distinctive for each molecule and, more importantly, independent of the nucleobase orientation, which can be served as electronic fingerprint for detection. We show that identifying the nucleobases can be achieved only though several specific regions or points in the diagram.
    Keywords: ATK; Application; single-electron transistor; set; sensor; dna sequencing; nucleoside; graphene nanopores; nucleotides; translocation; molecules; transport; capacitor; energies; device; holes; edge
    Area: molecular electronics; SET;
    BibTeX: 
    @article{Guo2012a,
  author = {Guo, Yan-Dong and Yan, Xiao-Hong and Xiao, Yang},
  title = {Computational Investigation of DNA Detection Using Single-Electron Transistor-Based Nanopore},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {40},
  pages = {21609--21614},
  doi = {http://dx.doi.org/10.1021/jp305909p}
}
    Jun He & Ke-Qiu Chen Rectifying and perfect spin filtering behavior realized by tailoring graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 J. Appl. Phys.
    Vol. 112(11), 114319-5     		 DOI  
    Abstract: An armchair graphene nanoribbon based electronic device with spin filtering and rectifying behavior is designed by means of molecular tailoring, and the electronic transport properties are calculated by using nonequilibrium Green's functions in combination with the density functional theory. The results show that the rectifying behavior can be observed in the junctions, and the rectifying ratio can be effectively tuned by edge doping. Furthermore, perfect spin polarization behavior can also be observed in the junctions.
    Keywords: ATK, Application, density functional theory, fullerene devices, graphene, green's function methods, nanoelectronics, nanoribbons, rectification, spin polarised transport, field-effect transistors, transport-properties, room-temperature, heterojunctions
    Area: graphene; spin
    BibTeX: 
    @article{He2012b,
  author = {He, Jun and Chen, Ke-Qiu},
  title = {Rectifying and perfect spin filtering behavior realized by tailoring graphene nanoribbons},
  journal = {J. Appl. Phys.},
  publisher = {AIP},
  year = {2012},
  volume = {112},
  number = {11},
  pages = {114319--5},
  doi = {http://dx.doi.org/10.1063/1.4768727}
}
    Golam Rasul Ahmed Jamal & Md Shamsul Arefin Empirical Equation of Tight Binding Model Parameter to Calculate Bandgap of Semiconducting Single Wall Carbon Nanotube

    [Abstract] [BibTeX]

    		 2012 Journal of Electrical Engineering, The Institution of Engineers, Bangladesh
    Vol. 37(2), 3     		 URL 
    Abstract: Both Mod 1 and Mod 2 type semiconducting single wall carbon nanotubes over a wide diameter range are studied separately to find their band gap trend. For accurate calculation of their band gaps, modification of nearest-neighbor hopping parameter of the tight-binding model is proposed by considering it as a function of nanotube chiral index and mod value. A simple empirical equation for the nearest-neighbor hopping parameter is presented to produce band gaps of these nanotubes that agree well with simulated data. Empirical data are also compared with experimental data and found to be in excellent agreement with it after adding a flat correction.
    Keywords: ATK-SE; Application; tight-binding; carbon nanotube; band gap; nearest neighbor hopping parameter; tight-binding model; chiral index
    Area: nanotubes
    BibTeX: 
    @article{Jamal2012,
  author = {Golam Rasul Ahmed Jamal and Md Shamsul Arefin},
  title = {Empirical Equation of Tight Binding Model Parameter to Calculate Bandgap of Semiconducting Single Wall Carbon Nanotube},
  journal = {Journal of Electrical Engineering, The Institution of Engineers, Bangladesh},
  year = {2012},
  volume = {37},
  number = {2},
  pages = {3},
  url = {http://www.banglajol.info/bd/index.php/JEE/article/view/12671}
}
    Ahmed Mahmoud & Paolo Lugli Designing the rectification behavior of molecular diodes

    [Abstract] [BibTeX]

    		 2012 J. Appl. Phys.
    Vol. 112(11), 113720-5     		 DOI  
    Abstract: Thanks to major advances in chemical and fabrication processes, various electronic devices based on single molecules have been demonstrated. On the theoretical level, many attempts have been made to provide a clear view of the charge transport mechanism through molecules. However, the overall picture is not yet complete. In this study, we show that the rectification of a molecular device can be controlled by enforcing the potential drop profile along the molecule. The insertion of a resistive molecular path near the metallic electrode(s) can drastically alter the rectification behavior. Our observation paves the way for a better control of molecular devices.
    Keywords: ATK-SE; Application; diodes; molecular electronics; transport; nanostructures; protonation; inversion; device
    Area: molecular electronics
    BibTeX: 
    @article{Mahmoud2012a,
  author = {Mahmoud, Ahmed and Lugli, Paolo},
  title = {Designing the rectification behavior of molecular diodes},
  journal = {J. Appl. Phys.},
  publisher = {AIP},
  year = {2012},
  volume = {112},
  number = {11},
  pages = {113720--5},
  doi = {http://dx.doi.org/10.1063/1.4768924}
}
    Yukihito Matsuura Electron Transport in Polymeric µ-Cyclopentadienylelement Complexes of the Main Group Elements

    [Abstract] [BibTeX]

    		 2012 Molecular Crystals and Liquid Crystals
    Vol. 569(1)Molecular Crystals and Liquid Crystals, 103-111     		 DOI  
    Abstract: I examined electrical conduction in polymeric µ-cyclopentadienylelement (Cp-E) complexes of the main group elements using the nonequilibrium Green's function formalism with the density functional theory. The polymeric Cp-E complexes of group 1 elements, which had ionic Cp-E bonds, showed very low conductance. In contrast, the polymeric Cp-E complexes of groups 13 and 14 elements exhibited enhanced n-type electrical conduction when a bias was applied between the electrodes, because the delocalized electronic states of the lowest unoccupied molecular orbital were within the bias window.
    Keywords: ATK; Application; molecular electronics; cyclopentadienyl complex; DFT; electron transport; NEGF
    Area: molecular electronics
    BibTeX: 
    @article{Matsuura2012a,
  author = {Matsuura, Yukihito},
  title = {Electron Transport in Polymeric µ-Cyclopentadienylelement Complexes of the Main Group Elements},
  booktitle = {Molecular Crystals and Liquid Crystals},
  journal = {Molecular Crystals and Liquid Crystals},
  publisher = {Taylor & Francis},
  year = {2012},
  volume = {569},
  number = {1},
  pages = {103--111},
  doi = {http://dx.doi.org/10.1080/15421406.2012.689575}
}
    Fanben Meng, Yves-Marie Hervault, Lucie Norel, Karine Costuas, Colin Van Dyck, Victor Geskin, Jerome Cornil, Huey Hoon Hng, Stephane Rigaut & Xiaodong Chen Photo-modulable molecular transport junctions based on organometallic molecular wires

    [Abstract] [BibTeX]

    		 2012 Chem. Sci.
    Vol. 3(10), 3113-3118     		 DOI  
    Abstract: Photo-modulable molecular transport junctions are developed via on-wire lithography-fabricated nanogaps functionalized with a dithienylethene unit bearing two ruthenium fragments. A reversible and repeatable bi-state conductive switching upon alternate irradiation of UV and visible light can be distinctly observed. Theoretical calculations further suggest that bi-directional isomerization is due to the ruthenium moieties that modulate judiciously the electronic coupling between the photochromic part and the metal electrodes, and that the differences in electronic structure between the two isomers (open and closed states) are responsible for conductivity switching.
    Keywords: ATK; Application; scanning-tunneling-microscopy; different oxidation-states; carbon-rich bridges; theoretical investigations; conductance; electronics; complexes; devices; ruthenium; temperature
    Area: molecular electronics
    BibTeX: 
    @article{Meng2012,
  author = {Meng, Fanben and Hervault, Yves-Marie and Norel, Lucie and Costuas, Karine and Van Dyck, Colin and Geskin, Victor and Cornil, Jerome and Hng, Huey Hoon and Rigaut, Stephane and Chen, Xiaodong},
  title = {Photo-modulable molecular transport junctions based on organometallic molecular wires},
  journal = {Chem. Sci.},
  publisher = {The Royal Society of Chemistry},
  year = {2012},
  volume = {3},
  number = {10},
  pages = {3113--3118},
  doi = {http://dx.doi.org/10.1039/C2SC20323E}
}
    Yuta Tsuji & Kazunari Yoshizawa Current Rectification through pi-pi Stacking in Multilayered Donor-Acceptor Cyclophanes

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(50)The Journal of Physical Chemistry C, 26625-26635     		 DOI  
    Abstract: Extended pi-stacked molecules have attracted much attention since they play an essential role in both electronic devices and biological systems. In this article electron transport properties of a series of multilayered cyclophanes with the hydroquinone donor and quinone acceptor units in the external positions are theoretically studied with applications to molecular rectifiers in mind. Calculations of electron transport through the pi-pi stacked structures in the multilayered cyclophanes are performed by using nonequilibrium Green?s function method combined with density functional theory. Calculated transmission spectra show that the conductance decreases exponentially with the length of the molecule with a decay factor of 0.75 Å^-1, which lies for the values between pi-conjugated molecules and sigma-bonded molecules. Applied bias calculations provide current-voltage curves, which exhibit good rectifying behavior. The rectification mechanism in the coherent transport regime is qualitatively explained by the response of the frontier orbital energy levels, especially LUMO levels, to the applied bias, where the rectifying direction is expected to be opposite to the Aviram-Ratner model. The maximum value of rectification ratio increases with an increase in the number of stacking layers due to the effective separation of the donor and acceptor parts, where effects from the opposite electrodes to the donor and acceptor are negligible. Multilayered donor?acceptor cyclophanes are suitable materials for investigating the relationship among electron transport properties, rectification properties, and molecular length (separation between the donor and acceptor parts).
    Keywords: ATK; Application; molecular electronics; generalized gradient approximation; charge-transfer interactions; single-molecule junctions; electron-transport; layered compounds; metal-electrodes; orbital views; conductance; wires; benzene
    Area: molecular electronics
    BibTeX: 
    @article{Tsuji2012a,
  author = {Tsuji, Yuta and Yoshizawa, Kazunari},
  title = {Current Rectification through pi-pi Stacking in Multilayered Donor-Acceptor Cyclophanes},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {50},
  pages = {26625--26635},
  doi = {http://dx.doi.org/10.1021/jp308849t}
}
    Huaping Xiao, Yuanping Chen, Yuee Xie, Tao Ouyang, Ye Zhang & Jianxin Zhong The modification of central B/N atom chain on electron transport of graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 J. Appl. Phys.
    Vol. 112(11), 113713-5     		 DOI  
    Abstract: The electronic transport properties of hybrid graphene nanoribbons constructed by substituting C atom chain into B (N) atom chain are investigated through using the density functional theory in combination with the nonequilibrium Green's function method. It is found that the hybrid nanoribbon with armchair edge transits from semiconducting to metallic. While the transport properties of hybrid B (N) system with zigzag edge are highly improved with the transmission conductance around the Fermi level increasing to 6G0 (5G0). All these unique transport properties are mainly attributed to the coupling effect between B (N) atoms and C atoms at the interface of hybrid systems, which introduces a pair of bonding and antibonding bands around the Fermi level. The results indicate that such hybrid system is an effective way to modulate the transport properties of graphene nanoribbons.
    Keywords: density functional theory, electrical conductivity transitions, Fermi level, graphene, Green's function methods, metal-insulator transition, nanoribbons, phase, ATK, Application
    Area: graphene
    BibTeX: 
    @article{Xiao2012a,
  author = {Xiao, Huaping and Chen, Yuanping and Xie, Yuee and Ouyang, Tao and Zhang, Ye and Zhong, Jianxin},
  title = {The modification of central B/N atom chain on electron transport of graphene nanoribbons},
  journal = {J. Appl. Phys.},
  publisher = {AIP},
  year = {2012},
  volume = {112},
  number = {11},
  pages = {113713--5},
  doi = {http://dx.doi.org/10.1063/1.4768719}
}
    Yuqing Xu, Bin Cui, Guomin Ji, Dongmei Li & Desheng Liu Effect of the orientation of nitro group on the electronic transport properties in single molecular field-effect transistors

    [Abstract] [BibTeX]

    		 2013 Phys. Chem. Chem. Phys.
    Vol. 15(3), 832-836     		 DOI  
    Abstract: Molecular devices with nitro groups display unique electronic transport properties in experiments. By applying the non-equilibrium Green's function combined with density functional theory, we find that the orientation of the nitro group with respect to the backbone of the molecule has a crucial effect on the device performance and can show unusual experimental phenomena. Furthermore, molecular devices with a nitro group are sensitive to gate voltage and suitable for making effective single molecular field-effect transistors. These results provide an important theoretical support to experiments and the design of future molecular devices by using nitro groups.
    Keywords: ATK; Application; molecular electronics; single molecular field-effect transistor; switch; quantum transport
    Area: molecular electronics
    BibTeX: 
    @article{Xu2013,
  author = {Xu, Yuqing and Cui, Bin and Ji, Guomin and Li, Dongmei and Liu, Desheng},
  title = {Effect of the orientation of nitro group on the electronic transport properties in single molecular field-effect transistors},
  journal = {Phys. Chem. Chem. Phys.},
  publisher = {The Royal Society of Chemistry},
  year = {2013},
  volume = {15},
  number = {3},
  pages = {832--836},
  doi = {http://dx.doi.org/10.1039/C2CP41480E}
}
    Wei Yao, K.L. Yao, G.Y. Gao, S.C. Zhu & H.H. Fu Anisotropic transport properties of zinc-blend ZnTe/CrTe heterogeneous junction nanodevices

    [Abstract] [BibTeX]

    		 2012 J. Appl. Phys.
    Vol. 112(10), 103717-6     		 DOI  
    Abstract: Motivated by the molecular-beam epitaxial growth of zinc-blend-type CrTe thin films on ZnTe, we present a theoretical study on the spin-polarized transport properties of ZnTe/CrTe p-n junction as spin diode and CrTe/ZnTe/CrTe magnetic tunnel junction for (001) and (011) surfaces. Both ZnTe(001)/CrTe(001) and ZnTe(011)/CrTe(011) p-n junctions show excellent spin diode effect, the majority spin current of positive voltage is much larger than that of negative voltage and the minority spin current is absolutely inhibited. The ZnTe(001)/CrTe(001) p-n junction has lower "turn off" current and higher rectification ratio (about 10^5) than the ZnTe(011)/CrTe(011) which shows obvious anisotropy. We also find that the tunneling magneto resistance ratio of the CrTe/ZnTe/CrTe magnetic tunnel junction is up to about 4x10^9%.
    Keywords: ATK, , Application, chromium compounds, diodes, electron spin polarisation, molecular beam epitaxial growth, nanotechnology, p-n junctions, thin films, tunnelling magnetoresistance, wide band gap semiconductors, zinc compounds, MTJ, half-metallic ferromagnets, molecular-beam epitaxy, room-temperature, spintronics, magnetoresistance, semiconductors
    Area: interfaces; nvm; semi; spin
    BibTeX: 
    @article{Yao2012,
  author = {Yao, Wei and Yao, K. L. and Gao, G. Y. and Zhu, S. C. and Fu, H. H.},
  title = {Anisotropic transport properties of zinc-blend ZnTe/CrTe heterogeneous junction nanodevices},
  journal = {J. Appl. Phys.},
  publisher = {AIP},
  year = {2012},
  volume = {112},
  number = {10},
  pages = {103717--6},
  doi = {http://dx.doi.org/10.1063/1.4767935}
}
    J. Yu, G.L. Zhang, Y. Shang, K.D. Wang, H. Zhang, M. Sun, B. Liu & T. Zeng Transport properties of CNT/oligosilane/CNT heterojunctions

    [Abstract] [BibTeX]

    		 2013 Physica B: Condensed Matter
    Vol. 410(0), 237-243     		 DOI  
    Abstract: Combining the non-equilibrium Green's function formalism with density functional theory, the transport properties of nine CNT/oligosilane/CNT heterojunctions were systematically studied. We have found that the incorporation of oligosilane linkage to the carbon nanotube mouth could significantly tune the transport properties compared with the pure oligosilane and pure CNT. The P- and B-dopings upon the oligosilane moiety could not only enhance the conductivity but also give rise to multiple negative differential resistance behavior for the CNT/oligosilane/CNT heterojunctions. The concentration of heteroatom plays an important role in the transport properties of the CNT/oligosilane/CNT heterojunctions, while the number of the oligosilane linkage exerts little effect on the conductivity. The B-doped CNT/oligosilane/CNT heterojunctions show higher conductivity than those of the P-doped ones. The p-n junction caused by B- and P-codopings exhibits a rectifying effect and the rectification ratio is up to 7.19.
    Keywords: ATK; Application; theoretical study; transport property; carbon nanotube; oligosilane; doping; negative differential resistance; walled carbon nanotubes; silicon nanowire; peptide linkages; ab-initio; conductance; transistors; electrodes; molecules; diode
    Area: nanotubes
    BibTeX: 
    @article{Yu2013,
  author = {Yu, J. and Zhang, G.L. and Shang, Y. and Wang, K.D. and Zhang, H. and Sun, M. and Liu, B. and Zeng, T.},
  title = {Transport properties of CNT/oligosilane/CNT heterojunctions},
  journal = {Physica B: Condensed Matter},
  year = {2013},
  volume = {410},
  number = {0},
  pages = {237--243},
  doi = {http://dx.doi.org/10.1016/j.physb.2012.11.016}
}
    C.X. Zhang, Huaping Xiao, Chaoyu He, L. Xue, K.W. Zhang, L.Z. Sun & Jianxin Zhong Effects of contact oxidization on the transport properties of Au/ZGNR junctions

    [Abstract] [BibTeX]

    		 2012 Phys. Status Solidi RRL
    Vol. 6(12), 457-459     		 DOI  
    Abstract: The transport properties of the junction assembled by zigzag graphene nanoribbons (ZGNRs) and Au electrode (Au/ZGNR) are investigated using first-principles calculations. It is found that the Au/ZGNR junction behaves as a typical diode with Schottky barrier at the contact. Our results indicate that although the oxidization at the contact slightly influences the Schottky barrier, the I-V characteristic is effectively modulated. Such effect derives from the impact of the oxidization on the coupling between the ZGNRs and Au electrode.
    Keywords: ATK, Application, graphene nanoribbons, electronic transport, contact oxidization, gold electrodes, augmented-wave method, graphene nanoribbons, carbon nanotubes, electronics, oxide
    Area: graphene
    BibTeX: 
    @article{Zhang2012g,
  author = {Zhang, C. X. and Xiao, Huaping and He, Chaoyu and Xue, L. and Zhang, K. W. and Sun, L. Z. and Zhong, Jianxin},
  title = {Effects of contact oxidization on the transport properties of Au/ZGNR junctions},
  journal = {Phys. Status Solidi RRL},
  publisher = {WILEY-VCH Verlag},
  year = {2012},
  volume = {6},
  number = {12},
  pages = {457--459},
  doi = {http://dx.doi.org/10.1002/pssr.201206409}
}
    Yipeng An, Xinyuan Wei & Zhongqin Yang Improving electronic transport of zigzag graphene nanoribbons by ordered doping of B or N atoms

    [Abstract] [BibTeX]

    		 2012 Phys. Chem. Chem. Phys.
    Vol. 14(45), 15802-15806     		 DOI  
    Abstract: Using an ab initio method, we explored electronic structures and transport properties of zigzag graphene nanoribbons (ZGNRs) with ordered doping of B or N atoms. We find B or N atoms doping can increase significantly the conductance of the ZGNRs with an even number of zigzag chains due to additional conducting channels being induced and the breakdown of parity limitation. The higher the doping concentration, the larger the current amplification factor obtained. For the nanojunctions with one row B (or N) atoms, the current amplification factor can be larger when the doping position is near to the center, while for the junction with two rows, the trend is subtle due to the interactions between the two rows of B (or N) atoms. Negative differential resistive phenomena are found for the case of B doping at low concentrations and the case for N doping. The conductance of the ZGNR with odd numbers of zigzag chains can also be increased by doping of B or N atoms. More interestingly, the B or N doping can almost completely remove the even-odd effect on electronic transport of the ZGNRs. Our studies provide avenues to drastically improve the electronic transport of ZGNRs, helpful for graphene applications.
    Keywords: ATK; Application; doping; negative differential resistance; NDR; field-effect transistors
    Area: graphene
    BibTeX: 
    @article{An2012c,
  author = {An, Yipeng and Wei, Xinyuan and Yang, Zhongqin},
  title = {Improving electronic transport of zigzag graphene nanoribbons by ordered doping of B or N atoms},
  journal = {Phys. Chem. Chem. Phys.},
  publisher = {The Royal Society of Chemistry},
  year = {2012},
  volume = {14},
  number = {45},
  pages = {15802--15806},
  doi = {http://dx.doi.org/10.1039/C2CP42123B}
}
    L.N. Chen, C. Cao, X.Z. Wu, S.S. Ma, W.R. Huang & H. Xu Effects of partial hydrogenation on electronic transport properties in C60 molecular devices

    [Abstract] [BibTeX]

    		 2012 Solid State Communications
    Vol. 152(23), 2123-2127     		 DOI URL 
    Abstract: By using nonequilibrium Green's functions in combination with the density–function theory, we investigate electronic transport properties of molecular devices with pristine and partial hydrogenation. The calculated results show that the electronic transport properties of molecular devices can be modulated by partial hydrogenation. Interestingly, our results exhibit negative differential resistance behavior in the case of the imbalance H-adsorption in C60 molecular devices under low bias. However, negative differential resistance behavior cannot be observed in the case of the balance H-adsorption. A mechanism is proposed for the hydrogenation and negative differential resistance behavior.
    Keywords: ATK; Application; molecular device; transport property; hydrogenation; first-principles; fullerenes
    Area: molecular electronics;
    BibTeX: 
    @article{Chen2012a,
  author = {Chen, L.N. and Cao, C. and Wu, X.Z. and Ma, S.S. and Huang, W.R. and Xu, H.},
  title = {Effects of partial hydrogenation on electronic transport properties in C60 molecular devices},
  journal = {Solid State Communications},
  year = {2012},
  volume = {152},
  number = {23},
  pages = {2123--2127},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109812005315},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.09.011}
}
    Guomin Ji, Yuqing Xu, Bin Cui, Changfeng Fang, Xiangru Kong, Dongmei Li & Desheng Liu Rectifying behaviors of an Au/(C20)2/Au molecular device induced by the different positions of gate voltage

    [Abstract] [BibTeX]

    		 2012 RSC Adv.
    Vol. 2(30), 11349-11353     		 DOI  
    Abstract: The electronic transport properties of a gated Au/(C20)2/Au molecular device are studied using nonequilibrium Green's function in combination with density functional theory. The results show that different applied positions of the external transverse gate voltage can effectively tune the current-voltage (I-V) characteristic of molecular devices. Rectifying behaviors of the device can be realized when the gate voltage is applied asymmetrically on the left C20 molecule, and the rectification directions can also be modulated by the positive or negative value of the gate voltage. These results provide an important theoretical support to experiments and the design of a molecular rectifier.
    Keywords: ATK; Application; molecular electronics; fullerenes; rectification
    Area: molecular electronics; fullerenes
    BibTeX: 
    @article{Ji2012a,
  author = {Ji, Guomin and Xu, Yuqing and Cui, Bin and Fang, Changfeng and Kong, Xiangru and Li, Dongmei and Liu, Desheng},
  title = {Rectifying behaviors of an Au/(C20)2/Au molecular device induced by the different positions of gate voltage},
  journal = {RSC Adv.},
  publisher = {The Royal Society of Chemistry},
  year = {2012},
  volume = {2},
  number = {30},
  pages = {11349--11353},
  doi = {http://dx.doi.org/10.1039/C2RA21146G}
}
    Antonio J. Mota, Luis Ávarez de Cienfuegos, Sara P. Morcillo, Noelia Fuentes, Delia Miguel, Salvador Rodríguez-Bolívar, Francisco M. Gómez-Campos, Diego J. Cárdenas & Juan M. Cuerva Thermally Driven Nanofuses Based on Organometallic Rotors

    [Abstract] [BibTeX]

    		 2012 ChemPhysChem
    Vol. 13(17), 3857-3865     		 DOI  
    Abstract: Molecular design of chromium arenes are theoretically studied as a model for the development of novel thermally-driven molecular fuses. This study correlates the switching event with a partial disconnection of the molecule from the metallic electrode mediated by changes in the conformational states of the molecule directed by external stimuli. Moreover, the reversibility of the process (the reconnection to the metallic electrode) is also considered for these systems when a reversal voltage pulse (reset) is applied. The energetic requirements of the on and off states are correlated with temperature through the Arrhenius equation. To carry out this study we performed density functional theory (DFT) calculations.
    Keywords: ATK, Application, arene complexes, aromatic compounds, density functional calculations, electron transport, molecular motors; single molecular conductance; density-functional theory; aqueous-solution; junctions; electronics; transport; exchange; behavior
    Area: molecular electronics; thermo
    BibTeX: 
    @article{Mota2012,
  author = {Mota, Antonio J. and Ávarez de Cienfuegos, Luis and Morcillo, Sara P. and Fuentes, Noelia and Miguel, Delia and Rodríguez-Bolívar, Salvador and Gómez-Campos, Francisco M. and Cárdenas, Diego J. and Cuerva, Juan M.},
  title = {Thermally Driven Nanofuses Based on Organometallic Rotors},
  journal = {ChemPhysChem},
  publisher = {WILEY-VCH Verlag},
  year = {2012},
  volume = {13},
  number = {17},
  pages = {3857--3865},
  doi = {http://dx.doi.org/10.1002/cphc.201200544}
}
    Anurag Srivastava & Neha Tyagi Structural and electronic properties of AlX (X=P, As, Sb) nanowires: Ab initio study

    [Abstract] [BibTeX]

    		 2012 Materials Chemistry and Physics
    Vol. 137(1), 103-112     		 DOI URL 
    Abstract: Present paper discusses the structural stability and electronic properties of AlX (X = P, As and Sb) nanowires in its linear, zigzag, ladder, square and hexagonal type atomic configurations. The structural optimization has been performed in self consistence manner by using generalized gradient approximation with revised Perdew, Burke and Ernzerhof type parameterization. The study observes that in all the three nanowires, the square shaped atomic configuration is the most stable one. The calculated electronic band structures and density of states profile confirms the semiconducting behaviour of linear and zigzag shaped nanowires of AlP, whereas for AlAs and AlSb nanowires are metallic. The ground state properties have also been analysed in terms of bond length, bulk modulus and pressure derivative for all the nanowires along with their bulk counterpart. The lower bulk modulus of all the linear shaped geometries of AlX nanowires in comparison to its bulk counterpart indicates softening of the material at reduced dimension.
    Keywords: ATK; Application; nanostructures; semiconductors; ab initio calculations; band-structure; electronic structure; zincblende semiconductors; III-V; energetics
    Area: nanowires
    BibTeX: 
    @article{Srivastava2012f,
  author = {Srivastava, Anurag and Tyagi, Neha},
  title = {Structural and electronic properties of AlX (X=P, As, Sb) nanowires: Ab initio study},
  journal = {Materials Chemistry and Physics},
  year = {2012},
  volume = {137},
  number = {1},
  pages = {103--112},
  url = {http://www.sciencedirect.com/science/article/pii/S0254058412007572},
  doi = {http://dx.doi.org/10.1016/j.matchemphys.2012.08.046}
}
    Christian Wagner, Jörg Schuster & Thomas Gessner DFT investigations of the piezoresistive effect of carbon nanotubes for sensor application

    [Abstract] [BibTeX]

    		 2012 Phys. Status Solidi B
    Vol. 249(12), 2450-2453     		 DOI  
    Abstract: We investigate the piezoresistive effect of carbon nanotubes (CNTs) within density functional theory (DFT) aiming at application-relevant CNTs. CNTs are excellent candidates for the usage in nano-electromechanical sensors (NEMSs) due to their small band gap at zero strain leading to a finite resistivity at room temperature. The application of strain induces a band gap-opening leading to a tremendous change in the resistivity. DFT with the LDA approximation yields reasonable results for pure carbon systems like CNTs and is applied to calculate the electronic structure of experimentally relevant CNTs. For the transport part, a simple ballistic transport model based on the band gap is used. We compare our DFT results for the band gaps of strained CNTs to results of tight binding (TB) models. By introducing a scaling factor of $sqrt 2 $, an excellent agreement of the DFT data with TB model, published by Yang and Han [Phys. Rev. Lett. 85, 154 (2000)], is obtained.
    Keywords: ATK, Application, acceleration sensor, bandgap, carbon nanotube, density functional theory, electronic structure, nanoelectronics, nanotechnology, piezoresistance
    Area: nanotubes
    BibTeX: 
    @article{Wagner2012,
  author = {Wagner, Christian and Schuster, Jörg and Gessner, Thomas},
  title = {DFT investigations of the piezoresistive effect of carbon nanotubes for sensor application},
  journal = {Phys. Status Solidi B},
  publisher = {WILEY-VCH Verlag},
  year = {2012},
  volume = {249},
  number = {12},
  pages = {2450--2453},
  doi = {http://dx.doi.org/10.1002/pssb.201200113}
}
    Bing Yang, Ruixin Dong, Xunling Yan & Qiang Shi Recognizing nucleosides with transverse electronic transport via perpendicular direction of base planes for DNA sequencing

    [Abstract] [BibTeX]

    		 2012 Nanoscale Research Letters
    Vol. 7(1), 512     		 DOI  
    Abstract: Putting the four DNA nucleosides in the middle of gold [111] nanoelectrodes with base planes parallel to the electrode surface layer, we study the transverse electronic transport properties of four nucleosides along the direction of electrodes. First, the optimal distance of the electrodes is released. The results show that the optimal electrode distance to study transverse electronic transport characteristics of DNA nucleosides is about 0.68 nm. Second, we theoretically calculate the conductance and current of the four nucleosides via perpendicular direction of base planes in the bias range of [2, 2] V by exploiting the first principle theory. According to the calculated results, we propose three methods to recognize the nucleoside type in practice application.
    Keywords: ATK; Application; DNA; nucleoside; electronic transport; DNA sequencing; nucleotides
    Area: molecular electronics
    BibTeX: 
    @article{Yang2012c,
  author = {Yang, Bing and Dong, Ruixin and Yan, Xunling and Shi, Qiang},
  title = {Recognizing nucleosides with transverse electronic transport via perpendicular direction of base planes for DNA sequencing},
  journal = {Nanoscale Research Letters},
  year = {2012},
  volume = {7},
  number = {1},
  pages = {512},
  doi = {http://dx.doi.org/10.1186/1556-276X-7-512}
}
    Wei Yao, K.L. Yao, G.Y. Gao, H.H. Fu & S.C. Zhu Boron-doping controlled peculiar transport properties of graphene nanoribbon p-n junctions

    [Abstract] [BibTeX]

    		 2013 Solid State Communications
    Vol. 153(1), 46-52     		 DOI URL 
    Abstract: We construct two kinds of p-n junctions based on graphene nanoribbons with different doping concentration. The left part of junction is Boron-doped at the edge of zigzag-edge graphene nanoribbon, and the right part is Boron-doped at the center. The transport properties, calculated by nonequilibrium Green's function method combined with the density functional theory under external bias, show obvious rectification effect and interesting negative differential resistance phenomenon depending on Boron-doping density and position. Considering the interaction of charge carriers with impurity and the correlation between charges at the edges and center, the excellent nanoscale electronic devices have been achieved.
    Keywords: ATK; Application; graphene nanoribbon; boron doping; diode effect; negative differential resistance; NDR
    Area: graphene
    BibTeX: 
    @article{Yao2013,
  author = {Yao, Wei and Yao, K.L. and Gao, G.Y. and Fu, H.H. and Zhu, S.C.},
  title = {Boron-doping controlled peculiar transport properties of graphene nanoribbon p-n junctions},
  journal = {Solid State Communications},
  year = {2013},
  volume = {153},
  number = {1},
  pages = {46--52},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109812005546},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.10.009}
}
    Minggang Zeng, Wen Huang & Gengchiau Liang Spin-dependent thermoelectric effects in graphene-based spin valves

    [Abstract] [BibTeX]

    		 2013 Nanoscale
    Vol. 5(1), 200-208     		 DOI  
    Abstract: Using first-principles calculations combined with non-equilibrium Green's function (NEGF), we investigate spin-dependent thermoelectric effects in a spin valve which consists of zigzag graphene nanoribbon (ZGNR) electrodes with different magnetic configurations. We find that electron transport properties in the ZGNR-based spin valve are strongly dependent on the magnetic configurations. As a result, with a temperature bias, thermally-induced currents can be controlled by switching the magnetic configurations, indicating a thermal magnetoresistance (MR) effect. Moreover, based on the linear response assumption, our study shows that the remarkably different Seebeck coefficients in the various magnetic configurations lead to a very large and controllable magneto Seebeck ratio. In addition, we evaluate thermoelectric properties, such as the power factor, electron thermal conductance and figure of merit (ZT), of the ZGNR-based spin valve. Our results indicate that the power factor and the electron thermal conductance are strongly related to the transmission gap and electron-hole symmetry of the transmission spectrum. Moreover, the value of ZT can reach 0.15 at room temperature without considering phonon scattering. In addition, we investigate the thermally-controlled magnetic distributions in the ZGNR-based spin valve and find that the magnetic distribution, especially the local magnetic moment around the Ni atom, is strongly related to the thermal bias. The very large, multi-valued and controllable thermal magnetoresistance and Seebeck effects indicate the strong potential of ZGNR-based spin valves for extremely low-power consuming spin caloritronics applications. The thermally-controlled magnetic moment in the ZGNR-based spin valve indicates its possible applications for information storage.
    Keywords: ATK; Application; spin-dependent thermoelectric effects; spin valves; graphene; Seebeck; ZT; figure of merit; thermal magnetoresistance effect
    Area: graphene; spin; thermo
    BibTeX: 
    @article{Zeng2013,
  author = {Zeng, Minggang and Huang, Wen and Liang, Gengchiau},
  title = {Spin-dependent thermoelectric effects in graphene-based spin valves},
  journal = {Nanoscale},
  publisher = {The Royal Society of Chemistry},
  year = {2013},
  volume = {5},
  number = {1},
  pages = {200--208},
  doi = {http://dx.doi.org/10.1039/C2NR32226A}
}
    Daoli Zhang, Yuanlan Xu, Jianbing Zhang & Xiangshui Miao First-principles study of the electronic transport properties in (GaAs)n (n=2-4) nanocluster-based molecular junctions

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(45), 3272-3276     		 DOI URL 
    Abstract: In this program the geometric structures and electronic transport properties of a series of (GaAs)n ( n = 2 , 3 , 4 ) clusters are comparatively studied using non-equilibrium Green's function (NEGF) combined with density functional theory (DFT). It is find that all the GaAs nanocluster-based molecular junctions show metallic behavior at low biases ([-2 V , 2 V]) while negative differential resistance (NDR) appears at a certain high bias range. Our calculation shows that the current of (GaAs)3 nanocluster-based molecular junction is almost the smallest at any bias. The mechanisms of the current-voltage characteristics of all the three molecular junctions are proposed.
    Keywords: ATK; Application; GaAs nanocluster; molecular device; negative differential resistance; NDR
    Area: molecular electronics
    BibTeX: 
    @article{Zhang2012f,
  author = {Zhang, Daoli and Xu, Yuanlan and Zhang, Jianbing and Miao, Xiangshui},
  title = {First-principles study of the electronic transport properties in (GaAs)n (n=2-4) nanocluster-based molecular junctions},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {45},
  pages = {3272--3276},
  url = {http://www.sciencedirect.com/science/article/pii/S037596011200998X},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.09.023}
}
    Z.H. Zhang, C. Guo, G. Kwong & X.Q. Deng Electronic transport of nitrogen-capped monoatomic carbon wires between lithium electrodes

    [Abstract] [BibTeX]

    		 2013 Carbon
    Vol. 51(0), 313-321     		 DOI URL 
    Abstract: Nitrogen (N)-capped single-atom carbon wires are chemisorbed onto two identical Li (1 1 1) electrodes to construct nanodevices. First-principles calculations predict that devices with even and odd numbers of carbon wires would show dramatically different and unexpected electronic transport properties. An even number of wires shows a metallic-like ballistic transport at low bias, a nonlinear current-voltage characteristic over the whole bias region, and a very striking negative differential resistance (NDR). An odd number of carbon wires shows the exact opposite behavior. Currents are very small and rise extreme slowly with bias, and no NDR is observed. The zero-bias conductance of an even number of carbon wires is rather high and reaches a value of about 20 times larger than that for an odd number of wires. These intriguing phenomena can be attributed to changes in the molecular states due to charge transfer doping.
    Keywords: ATK; Application; negative differential resistance; NDR; molecular electronics;
    Area: molecular electronics
    BibTeX: 
    @article{Zhang2013,
  author = {Zhang, Z.H. and Guo, C. and Kwong, G. and Deng, X.Q.},
  title = {Electronic transport of nitrogen-capped monoatomic carbon wires between lithium electrodes},
  journal = {Carbon},
  year = {2013},
  volume = {51},
  number = {0},
  pages = {313--321},
  url = {http://www.sciencedirect.com/science/article/pii/S0008622312007105},
  doi = {http://dx.doi.org/10.1016/j.carbon.2012.08.058}
}
    Peng Zhao, De-Sheng Liu, Shu-Juan Li & Gang Chen Giant low bias negative differential resistance induced by nitrogen doping in graphene nanoribbon

    [Abstract] [BibTeX]

    		 2012 Chemical Physics Letters
    Vol. 554(0), 172-176     		 DOI URL 
    Abstract: By applying nonequilibrium Green's function formalism in combination with density functional theory, we have investigated the electronic transport properties of armchair graphene nanoribbon devices with periodic nitrogen-doping. Giant negative differential resistance behaviors with peak-to-valley ratio up to the order of 10^5 can be obtained in the mV bias regime by tuning the position and the concentration of the dopants. The negative differential resistance behavior is understood in terms of the evolution of the transmission spectrum and band structures with applied bias combined with the symmetry analyses of the Bloch wave functions of the corresponding subbands.
    Keywords: ATK; Application; graphene; doping;
    Area: graphene
    BibTeX: 
    @article{Zhao2012i,
  author = {Zhao, Peng and Liu, De-Sheng and Li, Shu-Juan and Chen, Gang},
  title = {Giant low bias negative differential resistance induced by nitrogen doping in graphene nanoribbon},
  journal = {Chemical Physics Letters},
  year = {2012},
  volume = {554},
  number = {0},
  pages = {172--176},
  url = {http://www.sciencedirect.com/science/article/pii/S0009261412012109},
  doi = {http://dx.doi.org/10.1016/j.cplett.2012.10.045}
}
    P. Zhao, D.S. Liu, S.J. Li & G. Chen Rectifying behavior in nitrogen-doped zigzag single-walled carbon nanotube junctions

    [Abstract] [BibTeX]

    		 2012 Solid State Communications
    Vol. 152(22), 2040-2044     		 DOI URL 
    Abstract: Using first-principles density functional theory and non-equilibrium Green's function formalism for quantum transport calculation, we have investigated the electronic transport properties of (8,0), (9,0) and (13,0) zigzag single-walled carbon nanotube junctions with one undoped and one nitrogen-doped zigzag carbon nanotube electrode. Our results show that the transport properties are strongly dependent on the magnitude of energy gap of carbon nanotube. Large rectifying behavior can be obtained in the junction with large energy gap. The observed rectifying behavior are explained in terms of the evolution of the transmission spectra and energy band structures with applied bias voltage combined with molecular projected self-consistent Hamiltonian eigenstates analysis.
    Keywords: ATK; Application; carbon nanotube; electronic transport; rectifying; negative differential resistance; transport-properties; devices; microtubules; conductance
    Area: nanotubes
    BibTeX: 
    @article{Zhao2012j,
  author = {Zhao, P. and Liu, D.S. and Li, S.J. and Chen, G.},
  title = {Rectifying behavior in nitrogen-doped zigzag single-walled carbon nanotube junctions},
  journal = {Solid State Communications},
  year = {2012},
  volume = {152},
  number = {22},
  pages = {2040--2044},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109812004784},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.08.013}
}
    Wen-Kai Zhao, Chuan-Lu Yang, Mei-Shan Wang & Xiao-Guang Ma Effects of electrode orientation on the transport properties of pyridine-terminated dithienylethene light molecule switch under bias

    [Abstract] [BibTeX]

    		 2013 Solid State Communications
    Vol. 153(1), 1-7     		 DOI  
    Abstract: Prior to this work, the effects of the electrode orientation and the bias voltage on the pyridine-terminated dithienylethene molecules have not been investigated, although the switching effect of the molecules have been reported experimentally. Using the first-principles density-functional theory and nonequilibrium Green's function formalism, the present study examined the switching behaviors of open-ring and closed-ring forms of pyridine-terminated dithienylethene molecules between different crystallographic orientations of electrodes and under different bias voltages. The characteristics of I-V curves are investigated, and the negative differential resistance behavior is observed for the open-ring forms with different electrodes.
    Keywords: ATK; Application; molecular switch; electronic transport; negative differential resistance; ndr; generalized gradient approximation; nanowire building-blocks; field-effect transistors; quantum transport; logic gates; conductance; junctions; devices
    Area: molecular electronics
    BibTeX: 
    @article{Zhao2013,
  author = {Zhao, Wen-Kai and Yang, Chuan-Lu and Wang, Mei-Shan and Ma, Xiao-Guang},
  title = {Effects of electrode orientation on the transport properties of pyridine-terminated dithienylethene light molecule switch under bias},
  journal = {Solid State Communications},
  year = {2013},
  volume = {153},
  number = {1},
  pages = {1--7},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.10.001}
}
    Lin Zhu & Shiv N. Khanna Quantum spin transport through magnetic superatom dimer (Cs[sub 8]V-Cs[sub 8]V)

    [Abstract] [BibTeX]

    		 2012 J. Chem. Phys.
    Vol. 137(16), 164311-6     		 DOI  
    Abstract: Theoretical studies of the spin transport through a magnetic superatom dimer (Cs8V)-(Cs8V) have been carried out within a density functional theory combined with nonequilibrium Green's-function formalism. It is shown that the electronic transport is sensitive to the binding site as well as the contact distance between the dimer and the electrode, and that the conductance at zero bias exhibits an oscillatory behavior as a function of the contact distance. The conductance in ferromagnetic state shows an unusually high spin polarization that exceeds 80% at large separations. The I-V curve shows negative differential resistance for specific contact distances, whose origin lies in the shift of frontier energy levels as well as the charged state of the superatom, under external bias.
    Keywords: caesium alloys, contact resistance, density functional theory, electric admittance, ferromagnetic materials, Green's function methods, metal clusters, molecular magnetism, spin polarised transport, vanadium alloys, ATK, Application
    Area: molecular electronics; spin
    BibTeX: 
    @article{Zhu2012a,
  author = {Zhu, Lin and Khanna, Shiv N.},
  title = {Quantum spin transport through magnetic superatom dimer (Cs[sub 8]V-Cs[sub 8]V)},
  journal = {J. Chem. Phys.},
  publisher = {AIP},
  year = {2012},
  volume = {137},
  number = {16},
  pages = {164311--6},
  doi = {http://dx.doi.org/10.1063/1.4763461}
}
    Si-Cong Zhu, Kai-Lun Yao, Guo-Ying Gao & Yun Ni Spin-dependent transport in graphene nanoribbons adsorbed with vanadium in different positions

    [Abstract] [BibTeX]

    		 2013 Solid State Communications
    Vol. 155(0), 40-44     		 DOI URL 
    Abstract: The spin-polarized quantum transport properties of graphene nanoribbons (GNRs) adsorbed with vanadium atoms and terminated with hydrogen are investigated by density functional theory (DFT) associated with nonequilibrium Green's function theory (NGFT). The spin current behaves nonlinearly against bias voltage for the 4-zigzag graphene nanoribbons (ZGNRs), even changing signal at certain voltages due to specific features of the coupling between molecular states and magnetic leads; For the V-adsorbed 7-armchair graphene nanoribbons (ACGNRs), the transmission coefficients is dramatical large. All these results suggest that the present structures are suitable for nanoelectronics and spintronics applications.
    Keywords: ATK; Application; graphene nanoribbons; bias-current; nonlinearly; tunneling; spin; doping; dopant;
    Area: graphene; spin
    BibTeX: 
    @article{Zhu2013,
  author = {Zhu, Si-Cong and Yao, Kai-Lun and Gao, Guo-Ying and Ni, Yun},
  title = {Spin-dependent transport in graphene nanoribbons adsorbed with vanadium in different positions},
  journal = {Solid State Communications},
  year = {2013},
  volume = {155},
  number = {0},
  pages = {40--44},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109812006084},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.11.001}
}
    A. Blom & K. Stokbro Towards realistic atomic-scale modeling of nanoscale devices

    [Abstract] [BibTeX]

    		 2011 Nanotechnology (IEEE-NANO), 2011 11th IEEE Conference on, 1487-1492  DOI  
    Abstract: On the nanoscale, electrical currents behave radically different compared to on the microscale. As the active regions become comparable to or smaller than the mean-free path of the material, it becomes necessary to describe the electron transport by quantum-mechanical methods instead of using classical relations like Ohm's law. Over the past decade, methods for computing electron tunneling currents in nanosized junctions have evolved steadily, and are now approaching a sophistication where they can provide real assistance in the development of novel semiconductor materials and devices. At the same time, the industry's demand for such solutions is rising rapidly to meet the challenges both above and under the 16 nm node. In this paper we provide an overview of the current state-of-the-art of the field of how to model electrical currents on the nanoscale, using atomic-scale simulations.
    Keywords: ATK, Application, Review, electron mobility, nanoelectronics, semiconductor device models, technology CAD (electronics), tunnelling, active regions, atomic-scale modeling, atomic-scale simulation, electron transport, electron tunneling current, nanoscale devices, nanoscale electrical currents, nanosized junctions, quantum-mechanical method, semiconductor device, semiconductor materials
    Area: molecular electronics; semi; graphene, nanotubes
    BibTeX: 
    @inproceedings{Blom2011,
  author = {Blom, A. and Stokbro, K.},
  title = {Towards realistic atomic-scale modeling of nanoscale devices},
  booktitle = {Nanotechnology (IEEE-NANO), 2011 11th IEEE Conference on},
  year = {2011},
  pages = {1487--1492},
  doi = {http://dx.doi.org/10.1109/NANO.2011.6144584}
}
    A.F. Kuloglu, B. Sarikavak-Lisesivdin, S.B. Lisesivdin & E. Ozbay First-principles calculations of Pd-terminated symmetrical armchair graphene nanoribbons

    [Abstract] [BibTeX]

    		 2013 Computational Materials Science
    Vol. 68(0), 18-22     		 DOI URL 
    Abstract: The effects of Palladium (Pd) termination on the electronic properties of armchair graphene nanoribbons (AGNRs) were calculated by using ab initio calculations. After a geometric optimization process, the electronic band structures, density of states, and binding energies of AGNRs with Na = 5-15 were calculated. Pd-termination was found to significantly influence the electronic properties of AGNRs. In DOS, many Q0D and Q1D type states were observed. Binding energy (BE) for single-side or both-side Pd-terminated structures represents characteristic drops with the increasing GNR width. With the increasing GNR width, the BEs of these structures become similar to hydrogenated structures. Because of the GNR width, dependent BE also gave information on the possible stiffness information, in which all of this information can be used in studies where controlled binding to graphene is required.
    Keywords: ATK; Application; Palladium; termination; passivation; graphene; GNR; nanoribbon; electronic properties; ab initio; adsorption; density of states; films
    Area: graphene
    BibTeX: 
    @article{Kuloglu2013,
  author = {Kuloglu, A.F. and Sarikavak-Lisesivdin, B. and Lisesivdin, S.B. and Ozbay, E.},
  title = {First-principles calculations of Pd-terminated symmetrical armchair graphene nanoribbons},
  journal = {Computational Materials Science},
  year = {2013},
  volume = {68},
  number = {0},
  pages = {18--22},
  url = {http://www.sciencedirect.com/science/article/pii/S0927025612006003},
  doi = {http://dx.doi.org/10.1016/j.commatsci.2012.10.011}
}
    Ruge Quhe, Ruixiang Fei, Qihang Liu, Jiaxin Zheng, Hong Li, Chengyong Xu, Zeyuan Ni, Yangyang Wang, Dapeng Yu, Zhengxiang Gao & Jing Lu Tunable and sizable band gap in silicene by surface adsorption

    [Abstract] [BibTeX]

    		 2012 Sci. Rep.
    Vol. 2, 853     		 DOI  
    Abstract: Opening a sizable band gap without degrading its high carrier mobility is as vital for silicene as for graphene to its application as a high-performance field effect transistor (FET). Our density functional theory calculations predict that a band gap is opened in silicene by single-side adsorption of alkali atom as a result of sublattice or bond symmetry breaking. The band gap size is controllable by changing the adsorption coverage, with an impressive maximum band gap up to 0.50 V. The ab initio quantum transport simulation of a bottom-gated FET based on a sodium-covered silicene reveals a transport gap, which is consistent with the band gap, and the resulting on/off current ratio is up to 10^8. Therefore, a way is paved for silicene as the channel of a high-performance FET.
    Keywords: ATK; Application; silicene; graphene; field-effect transistor; FET;
    Area: graphene
    BibTeX: 
    @article{Quhe2012a,
  author = {Quhe, Ruge and Fei, Ruixiang and Liu, Qihang and Zheng, Jiaxin and Li, Hong and Xu, Chengyong and Ni, Zeyuan and Wang, Yangyang and Yu, Dapeng and Gao, Zhengxiang and Lu, Jing},
  title = {Tunable and sizable band gap in silicene by surface adsorption},
  journal = {Sci. Rep.},
  publisher = {Macmillan Publishers Limited. All rights reserved},
  year = {2012},
  volume = {2},
  pages = {853},
  doi = {http://dx.doi.org/10.1038/srep00853}
}
    Sudhanshu Choudhary & S Qureshi Theoretical study on effect of radial and axial deformation on electron transport properties in a semiconducting Si-C nanotube

    [Abstract] [BibTeX]

    		 2012 Bulletin of Materials Science
    Vol. 35Bulletin of Materials Science, 713-718     		 DOI  
    Abstract: We investigate electron transport properties in a deformed (8, 0) silicon carbide nanotube by applying self consistent non-equilibrium Green's function formalism in combination with the density-functional theory to a two-probe molecular junction constructed from deformed nanotube. The results suggest significant reduction in threshold voltage in the case of both radially compressed and axially elongated (8, 0) SiCNTs, a large difference in current-voltage characteristics was observed. Analysis of frontier molecular orbitals (FMO) and transmission spectrum show bandgap reduction in deformed nanotubes. Deformation introduces electronic states near the Fermi level, enhancing the conduction properties of (8, 0) SiCNT. The FMOs and the orbitals corresponding to peaks in T(E) around Fermi level obviously has some major contributions from the deformed site. However, localization of the electronic state near the Fermi level is weak in (8, 0) SiCNT, possibly because of its large bandgap.
    Keywords: ATK; Application; nanotube; SiCNT; armchair-zigzag; defects; deformation
    Area: nanotubes
    BibTeX: 
    @article{Choudhary2012,
  author = {Choudhary, Sudhanshu and Qureshi, S},
  title = {Theoretical study on effect of radial and axial deformation on electron transport properties in a semiconducting Si-C nanotube},
  booktitle = {Bulletin of Materials Science},
  journal = {Bulletin of Materials Science},
  publisher = {Springer-Verlag},
  year = {2012},
  volume = {35},
  pages = {713-718},
  doi = {http://dx.doi.org/10.1007/s12034-012-0370-y}
}
    Qihang Liu, Linze Li, Yafei Li, Zhengxiang Gao, Zhongfang Chen & Jing Lu Tuning Electronic Structure of Bilayer MoS2 by Vertical Electric Field: A First-Principles Investigation

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(40)The Journal of Physical Chemistry C, 21556-21562     		 DOI  
    Abstract: Interest in the two-dimensional MoS2 material is consistently increasing because of its many potential applications, in particular in the next-generation nanoelectronic devices. By means of density functional theory computations, we systematically examined the effect of vertical electric field on the electronic structure of MoS2 bilayer. The bandgaps of the bilayer MoS2 monotonically decrease with an increasing vertical electric field. The critical electric fields, at which the semiconductor-to-metal transition occurs, are predicted to be in the range of 1.0-1.5 V/Å depending on different stacked conformations. Ab initio quantum transport simulations of a dual-gated bilayer MoS2 channel clearly confirm that the vertical electric field continuously manipulates the transmission gap of bilayer MoS2.
    Keywords: ATK; Application; MoS2; electric field; field effect transistor; FET; graphene; thin-films; nanosheets; graphene
    Area: graphene
    BibTeX: 
    @article{Liu2012,
  author = {Liu, Qihang and Li, Linze and Li, Yafei and Gao, Zhengxiang and Chen, Zhongfang and Lu, Jing},
  title = {Tuning Electronic Structure of Bilayer MoS2 by Vertical Electric Field: A First-Principles Investigation},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {40},
  pages = {21556--21562},
  doi = {http://dx.doi.org/10.1021/jp307124d}
}
    Zhiyong Wang, Hong Li, Zheng Liu, Zujin Shi, Jing Lu, Kazu Suenaga, Soon-Kil Joung, Toshiya Okazaki, Zhennan Gu, Jing Zhou, Zhengxiang Gao, Guangping Li, Stefano Sanvito, Enge Wang & Sumio Iijima Mixed Low-Dimensional Nanomaterial: 2D Ultranarrow MoS2 Inorganic Nanoribbons Encapsulated in Quasi-1D Carbon Nanotubes

    [Abstract] [BibTeX]

    		 2010 J. Am. Chem. Soc.
    Vol. 132(39)Journal of the American Chemical Society, 13840-13847     		 DOI  
    Abstract: Quasi-one-dimensional nanotubes and two-dimensional nanoribbons are two fundamental forms of nanostructures, and integrating them into a novel mixed low-dimensional nanomaterial is fascinating and challenging. We have synthesized a stable mixed low-dimensional nanomaterial consisting of MoS2 inorganic nanoribbons encapsulated in carbon nanotubes (which we call nanoburritos). This route can be extended to the synthesis of nanoburritos composed of other ultranarrow transition-metal chalcogenide nanoribbons and carbon nanotubes. The widths of previously synthesized MoS2 ribbons are greater than 50 nm, while the encapsulated MoS2 nanoribbons have uniform widths down to 1-4 nm and layer numbers down to 1-3, depending on the nanotube diameter. The edges of the MoS2 nanoribbons have been identified as zigzag-shaped using both high-resolution transmission electron microscopy and density functional theory calculations.
    Keywords: ATK; Application; MoS2; nanotube; experimental comparison; nanoburritos; nitrogenase FeMo-cofactor; graphene nanoribbons; electronic structure; electrochemical/chemical synthesis; magnetic properties; stability; nanoparticles; nanoclusters; transition
    Area: graphene; nanotubes
    BibTeX: 
    @article{Wang2010e,
  author = {Wang, Zhiyong and Li, Hong and Liu, Zheng and Shi, Zujin and Lu, Jing and Suenaga, Kazu and Joung, Soon-Kil and Okazaki, Toshiya and Gu, Zhennan and Zhou, Jing and Gao, Zhengxiang and Li, Guangping and Sanvito, Stefano and Wang, Enge and Iijima, Sumio},
  title = {Mixed Low-Dimensional Nanomaterial: 2D Ultranarrow MoS2 Inorganic Nanoribbons Encapsulated in Quasi-1D Carbon Nanotubes},
  booktitle = {Journal of the American Chemical Society},
  journal = {J. Am. Chem. Soc.},
  publisher = {American Chemical Society},
  year = {2010},
  volume = {132},
  number = {39},
  pages = {13840--13847},
  doi = {http://dx.doi.org/10.1021/ja1058026}
}
    Zhi-Qiang Fan, Zhen-Hua Zhang, Ming Qiu, Xiao-Qing Deng & Gui-Ping Tang The site effects of B or N doping on I-V characteristics of a single pyrene molecular device

    [Abstract] [BibTeX]

    		 2012 Appl. Phys. Lett.
    Vol. 101(7), 073104-5     		 DOI  
    Abstract: Using the non-equilibrium Green's function method combined with the density functional theory, the electronic transport properties of boron (B) or nitrogen (N) doped pyrene molecular devices are investigated. The results show that effects of B or N doping on I-V characteristics of a single pyrene molecular device are not constant and can be changed by varying doped sites. More importantly, significant negative differential resistance (NDR) behaviors are found in B-doped pyrene molecular devices. The peak-to-valley ratio which is a typical character of NDR behavior is also sensitive to the B doped site.
    Keywords: ATK; Application; boron; density functional theory; doping; Green's function methods; molecular electronics; nitrogen
    Area: molecular electronics
    BibTeX: 
    @article{Fan2012b,
  author = {Fan, Zhi-Qiang and Zhang, Zhen-Hua and Qiu, Ming and Deng, Xiao-Qing and Tang, Gui-Ping},
  title = {The site effects of B or N doping on I-V characteristics of a single pyrene molecular device},
  journal = {Appl. Phys. Lett.},
  publisher = {AIP},
  year = {2012},
  volume = {101},
  number = {7},
  pages = {073104--5},
  doi = {http://dx.doi.org/10.1063/1.4745842}
}
    Vihar P. Georgiev, W.M.C. Sameera & John E. McGrady Attenuation of Conductance in Cobalt Extended Metal Atom Chains

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(38)The Journal of Physical Chemistry C, 20163-20172     		 DOI  
    Abstract: Density functional theory, in conjunction with nonequilibrium Green?s functions, is used to explore the attenuation of the resistance of Cox wires along the series Co3(dpa)4(NCS)2, Co5(tpda)4(NCS)2, and Co7(teptra)4(NCS)2. At very low bias (0 < V < 25 mV) the conductance, G, decreases in the order G(Co3) > G(Co5) > G(Co7), consistent with experiment and with an anticipated inverse relationship between conductance and chain length. At higher voltages, however, the current-voltage responses of all three are striking nonlinear, and above 50 mV G(Co5) > G(Co3) > G(Co7). The very different behavior of the members of this homologous series can be traced to the different symmetries and multiplicities of their respective ground states, which in turn control the properties of the dominant transport channels.
    Keywords: ATK; Application; molecular electronics; bond-stretch isomerism; linear tricobalt compounds; string complexes; electron-transport; magnetic properties; tripyridyldiamido dianion; molecular junctions; crystal-structures; charge-transport; ab-initio; spin
    Area: molecular electronics; spin
    BibTeX: 
    @article{Georgiev2012,
  author = {Georgiev, Vihar P. and Sameera, W. M. C. and McGrady, John E.},
  title = {Attenuation of Conductance in Cobalt Extended Metal Atom Chains},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {38},
  pages = {20163--20172},
  doi = {http://dx.doi.org/10.1021/jp304807w}
}
    Xiao-Fei Li, Ling-Ling Wang, Ke-Qiu Chen & Yi Luo Strong current polarization and negative differential resistance in chiral graphene nanoribbons with reconstructed (2,1)-edges

    [Abstract] [BibTeX]

    		 2012 Appl. Phys. Lett.
    Vol. 101(7), 073101-5     		 DOI  
    Abstract: We investigate electronic structures and transport properties of chiral-graphene-nanoribbons (CGNRs) with reconstructed (2,1)-edges. First principles results reveal that the (2,1)-CGNRs can be either spin non-polarized or polarized, depending on whether the edges are H-saturated or unsaturated. H-saturated systems are semiconductors with width-dependent transmission gap, while unsaturated systems are metallic at non-polarized state or at antiferromagnetic state and they are semiconductors at ferromagnetic state. Moreover, unsaturated systems possess strong current polarizations (nearly 100%) and a striking negative differential resistance behavior (with a peak-to-valley ratio about 10^5). These remarkable properties suggest the potential application of (2,1)-CGNRs in molectronics and spintronics.
    Keywords: ATK; Application; ab initio calculations; antiferromagnetic materials; electrical resistivity; ferromagnetic materials; graphene; magnetic semiconductors; nanomagnetics; nanoribbons; negative resistance; spin polarised transport; spin
    Area: graphene; spin
    BibTeX: 
    @article{Li2012m,
  author = {Li, Xiao-Fei and Wang, Ling-Ling and Chen, Ke-Qiu and Luo, Yi},
  title = {Strong current polarization and negative differential resistance in chiral graphene nanoribbons with reconstructed (2,1)-edges},
  journal = {Appl. Phys. Lett.},
  publisher = {AIP},
  year = {2012},
  volume = {101},
  number = {7},
  pages = {073101--5},
  doi = {http://dx.doi.org/10.1063/1.4745506}
}
    Kazunari Yoshizawa An Orbital Rule for Electron Transport in Molecules

    [Abstract] [BibTeX]

    		 2012 Acc. Chem. Res.
    Vol. 45(9)Accounts of Chemical Research, 1612-1621     		 DOI  
    Abstract: The transfer of electrons in molecules and solids is an essential process both in biological systems and in electronic devices. Devices that take advantage of the unique electronic properties of a single molecule have attracted much attention, and applications of these devices include molecular wire, molecular memory, and molecular diodes. The so-called Landauer formula with Green's function techniques provides a basis for theoretical calculations of coherent electron transport in metal-molecule-metal junctions. We have developed a chemical way of thinking about electron transport in molecules in terms of frontier orbital theory. The phase and amplitude of the HOMO and LUMO of pi-conjugated molecules determine the essential properties of their electron transport. By considering a close relationship between Green's function and the molecular orbital, we derived an orbital rule that would help our chemical understanding of the phenomenon. First, the sign of the product of the orbital coefficients at sites r and s in the HOMO should be different from the sign of the product of the orbital coefficients at sites r and s in the LUMO. Second, sites r and s in which the amplitude of the HOMO and LUMO is large should be connected. The derived rule allows us to predict essential electron transport properties, which significantly depend on the route of connection between a molecule and electrodes. Qualitative analyses of the site-dependent electron transport in naphthalene (as shown in the graphics) demonstrate that connections 1-4, 1-5, 2-3, and 2-6 are symmetry-allowed for electron transmission, while connections 1-8 and 2-7 are symmetry-forbidden. On the basis of orbital interaction analysis, we have extended this rule to metal-molecule-metal junctions of dithiol derivatives in which two gold electrodes have direct contacts with a molecule through two Au-S bonds. Recently we confirmed these theoretical predictions experimentally by using nanofabricated mechanically controllable break junctions to measure the single-molecule conductance of naphthalene dithiol derivatives. The measurement of the symmetry-allowed 1,4-naphthalene dithiol shows a single-molecule conductance that exceeds that of the symmetry-forbidden 2,7-naphthalene dithiol by 2 orders of magnitude. Because the HOMO and LUMO levels and the HOMO-LUMO gaps are similar in the derivatives, the difference in the measured molecular conductances arises from the difference in the phase relationship of the frontier orbitals. Thus, the phase, amplitude, and spatial distribution of the frontier orbitals provide a way to rationally control electron transport properties within and between molecules.
    Keywords: ATK; Application; review; molecular electronics; nanosized graphite sheets; current-voltage characteristics; quantum transport; organic-molecules; aromatic-hydrocarbons; tunneling current; single-molecule; charge-transfer; ground-state; conductance
    Area: molecular electronics
    BibTeX: 
    @article{Yoshizawa2012,
  author = {Yoshizawa, Kazunari},
  title = {An Orbital Rule for Electron Transport in Molecules},
  booktitle = {Accounts of Chemical Research},
  journal = {Acc. Chem. Res.},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {45},
  number = {9},
  pages = {1612--1621},
  doi = {http://dx.doi.org/10.1021/ar300075f}
}
    Hong Li, Lu Wang, Qihang Liu, Jiaxin Zheng, Wai-Ning Mei, Zhengxiang Gao, Junjie Shi & Jing Lu High performance silicene nanoribbon field effect transistors with current saturation

    [Abstract] [BibTeX]

    		 2012 The European Physical Journal B - Condensed Matter and Complex Systems
    Vol. 85(8), 1-6     		 DOI  
    Abstract: We investigate field effect transistors (FETs) based on semiconducting armchair-edged silicene nanoribbons (ASiNRs) by using ab initio quantum transport calculations. These FETs have high performance with an I on/I off ratio of over 10^6 and a subthreshold swing as small as 90 mV/decade. Impressively, the output characteristic shows a saturation behavior. The drain-current saturation is an advantage with respect to device speed, but it's usually absent in carbon-based (e.g., graphene, graphene nanoribbons, carbon nanotubes, and organic single-molecule) FETs.
    Keywords: ATK; Application; silicene; field-effect transistor; FET; walled carbon nanotubes; nanowire transistors; graphene transistors; transport-properties; epitaxial-graphene; ab-initio; length
    Area: graphene
    BibTeX: 
    @article{Li2012l,
  author = {Li, Hong and Wang, Lu and Liu, Qihang and Zheng, Jiaxin and Mei, Wai-Ning and Gao, Zhengxiang and Shi, Junjie and Lu, Jing},
  title = {High performance silicene nanoribbon field effect transistors with current saturation},
  journal = {The European Physical Journal B - Condensed Matter and Complex Systems},
  publisher = {Springer Berlin / Heidelberg},
  year = {2012},
  volume = {85},
  number = {8},
  pages = {1--6},
  doi = {http://dx.doi.org/10.1140/epjb/e2012-30220-2}
}
    Zhi Yang, Shaoding Liu, Xuguang Liu, Yongzhen Yang, Xiuyan Li, Shijie Xiong & Bingshe Xu The magnetic and quantum transport properties of benzene-vanadium-borazine mixed sandwich clusters: a new kind of spin filter

    [Abstract] [BibTeX]

    		 2012 Journal of Physics: Condensed Matter
    Vol. 24(44), 445501-     		 DOI URL 
    Abstract: Using density functional theory and the non-equilibrium Green's function technique, we performed theoretical investigations on the magnetic and quantum transport properties of benzene-vanadium-borazine mixed organic/inorganic ligand sandwich clusters. The calculated results show that these finite sandwich clusters coupled to Ni electrodes exhibit novel quantum transport properties such as half-metallicity, negative differential resistance and spin-reversal effect, and can be viewed as a new kind of spin filter. However, for the infinite molecular wire, the ground state was identified as a ferromagnetic semiconductor with high stability. These findings suggest that the mixed organic/inorganic ligand sandwich clusters and molecular wires are promising materials for application in molecular electronics and spintronics.
    Keywords: ATK; Application; molecular electronics; spin filter; boron-nitride; magnetism; molecular wire; negative differential resistance; NDR; molecular electronic devices; ab-initio; decker sandwich; charge-transfer; complexes; ligand; wires; ferromagnetism; ferrocene; binding
    Area: molecular electronics; spin
    BibTeX: 
    @article{Yang2012b,
  author = {Yang, Zhi and Liu, Shaoding and Liu, Xuguang and Yang, Yongzhen and Li, Xiuyan and Xiong, Shijie and Xu, Bingshe},
  title = {The magnetic and quantum transport properties of benzene-vanadium-borazine mixed sandwich clusters: a new kind of spin filter},
  journal = {Journal of Physics: Condensed Matter},
  year = {2012},
  volume = {24},
  number = {44},
  pages = {445501--},
  url = {http://stacks.iop.org/0953-8984/24/i=44/a=445501},
  doi = {http://dx.doi.org/10.1088/0953-8984/24/44/445501}
}
    Manisha Aggarwal, Ashok Kumar & Inderpreet Kaur Computational Study on the Electronic Properties of Functionalized Graphene Nanoribbon

    [Abstract] [BibTeX]

    		 2012 International Journal for Science and Emerging Technologies with Latest Trends
    Vol. 4(1), 7-12     		 URL 
    Abstract: Graphene, the starting material for all the carbon nanostructures, has attracted the attention of all the researchers worldwide due to its remarkable electronic and transport properties like quantum Hall effect at room temperature, an ambipolar electric field effect along with ballistic conduction of charge carriers, tunable band gap and high elasticity. Graphene is a flat monolayer 2D system of carbon atoms organized into a honeycomb lattice with sp2 hybridization. Graphene is a zero band gap material which is the defining concept for semiconductor materials and essential for controlling the conductivity by electronic means. However bilayer graphene shows band gap of 0.25 eV when a vertical electric field is applied. A large number of methods have been employed to calculate graphene's properties; one of them is theoretical study using density functional theory (DFT) method. Here in this article we are calculating band structure, density of states and transmission spectrum using density functional theory calculations by varying the length and the width of graphene nanoribbon (GNR). Functionalization studies of GNR have also been conducted using ATK-DFT.
    Keywords: ATK; Application; graphene; density functional theory; band structure; functionalization
    Area: graphene
    BibTeX: 
    @article{Aggarwal2012,
  author = {Manisha Aggarwal and Ashok Kumar and Inderpreet Kaur},
  title = {Computational Study on the Electronic Properties of Functionalized Graphene Nanoribbon},
  journal = {International Journal for Science and Emerging Technologies with Latest Trends},
  year = {2012},
  volume = {4},
  number = {1},
  pages = {7-12},
  url = {http://www.ijsett.com/images/Paper(4)7-12.pdf}
}
    Anirban Basak, S K Manhas, Gaurav Kapil, Sudeb Dasgupta & Neeraj Jain A Simulation Study of the Effect of Platinum Contact on CNT Based Gas Sensors Using Self-Consistent Field with NEGF Method

    [Abstract] [BibTeX]

    		 2012 SISPAD, 169-172   
    Abstract: The electronic structure of the pi electrons of the CNT is highly affected by the presence of foreign molecules. This property can be utilized in CNT based gas sensing applications. In this work, we study bare zigzag CNT, NO2 adsorbed zigzag CNT, and Pt contacted NO2 adsorbed zigzag CNT to find the effectiveness of zigzag CNT and Pt in making a NO2 gas sensor. We find that bare zigzag CNT is a good material for NO2 detection and platinum make Schottky contact with zigzag CNT which can be used for gas sensing applications.
    Keywords: ATK; Application; nanotube; sensor
    Area: nanotubes
    BibTeX: 
    @inproceedings{Basak2012,
  author = {Anirban Basak and S K Manhas and Gaurav Kapil and Sudeb Dasgupta and Neeraj Jain},
  title = {A Simulation Study of the Effect of Platinum Contact on CNT Based Gas Sensors Using Self-Consistent Field with NEGF Method},
  booktitle = {SISPAD},
  year = {2012},
  pages = {169-172}
}
    S. Caliskan & M. Canturk Spin dependent transport behavior in small world networks

    [Abstract] [BibTeX]

    		 2012 The European Physical Journal B - Condensed Matter and Complex Systems
    Vol. 85(9), 1-8     		 DOI  
    Abstract: Density functional theory (DFT) combined with the non equilibrium Green's function formalism (NEGF) is applied to perform spin polarized transport calculations on small world network (SWN) systems consisting of atomic wires. Including the spin property in SWN structures leads to interesting electrical properties. It is revealed that the emerging spin polarization depends mainly on the SWN geometry given by the asymmetric distribution of loops joining the arbitrary atoms on the main chain. The spin-asymmetric behavior which yields the spin polarization is found to be largely determined by those loops which are close to the electrodes. However, spin polarization may vanish for a specific SWN structure due to symmetry.
    Keywords: ATK; Application; carbon atomic wire; atomic chain; spintronics; spin; generalized gradient approximation; quantized conductance; coherent transport; complex networks; quantum wires; point-contact; nanowires; semiconductors; nanomaterials; transmission
    Area: spin
    BibTeX: 
    @article{Caliskan2012,
  author = {Caliskan, S. and Canturk, M.},
  title = {Spin dependent transport behavior in small world networks},
  journal = {The European Physical Journal B - Condensed Matter and Complex Systems},
  publisher = {Springer Berlin / Heidelberg},
  year = {2012},
  volume = {85},
  number = {9},
  pages = {1--8},
  doi = {http://dx.doi.org/10.1140/epjb/e2012-30253-5}
}
    Jikun Ding, Qiming Shao, Jinyu Zhang & Zhiping Yu Comparison for Various Kinds of Hamiltonian in Graphene Nanoribbon Quantum Transport Calculation

    [Abstract] [BibTeX]

    		 2012 SISPAD, 352-355   
    Abstract: The band structure and transport of an armchair and the zigzag graphene nanoribbon (GNR) are calculated using different types of Hamiltonians, including density functional-based tight binding (DFTB), extended Hückel theory (EHT), tight binding (TB), and density functional theory (DFT). Only the pz orbit is used for the carbon atom in the TB Hamiltonian (pz-TB). The other four orbits are used for the carbon atoms in the DFTB and EHT Hamiltonians. The transport calculation is performed using non-equilibrium Green's function (NEGF). The results show that all Hamiltonians have consistent band structures and I-V characteristics. Although pz-TB has low accuracy in describing the defects on GNR, it can still provide qualitatively correct band structures and I-V curves.
    Keywords: ATK; ATK-SE; Application; graphene nanoribbon; DFTB; Hückel; EHT; DFT; NEGF; defects
    Area: graphene
    BibTeX: 
    @inproceedings{Ding2012,
  author = {Jikun Ding and Qiming Shao and Jinyu Zhang and and Zhiping Yu},
  title = {Comparison for Various Kinds of Hamiltonian in Graphene Nanoribbon Quantum Transport Calculation},
  booktitle = {SISPAD},
  year = {2012},
  pages = {352-355}
}
    J.C. Dong & H. Li Monoatomic Layer Electronics Constructed by Graphene and Boron Nitride Nanoribbons

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(32)The Journal of Physical Chemistry C, 17259-17267     		 DOI  
    Abstract: A new and simple kind of heterostructure nanoelectronics, which are free of metal electrodes, is constructed by a boron nitride nanoribbon (BNNR) seamlessly connected between two pieces of graphene nanoribbons (GNRs). The electron transport properties of devices based on such GNR-BNNR-GNR heterostructures are systematically investigated. The effects of vacancy, chirality, width, and boundary of nanoribbons on the electron transport properties of these devices are discussed. Energy gaps over 1 eV are observed in the electron transmission spectra of devices composed of these heterojunctions, indicating their pronounced field effect transistor (FET) characters. Removing hydrogen atoms at the boron edge of zigzag BNNR can result in 100% electron spin polarization in the GNR-BNNR-GNR FET. This study has implications for developing high-performance monatomic layer nanoelectronics with simple heterojunctions.
    Keywords: ATK; Application; graphene heterojunction; nanoribbon; boron-nitride; field effect transistor; FET; scale epitaxial graphene; bilayer graphene; transport
    Area: graphene
    BibTeX: 
    @article{Dong2012a,
  author = {Dong, J. C. and Li, H.},
  title = {Monoatomic Layer Electronics Constructed by Graphene and Boron Nitride Nanoribbons},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {32},
  pages = {17259--17267},
  doi = {http://dx.doi.org/10.1021/jp304189w}
}
    Pradyumna Goli Current-Voltage Characteristics of Graphene Nanoribbons in the Ballistic Transport Regime

    [Abstract] [BibTeX]

    		 2012 Journal of Nanoelectronics and Optoelectronics
    Vol. 7(4), 381-385     		 DOI  
    Abstract: Extraordinary properties of graphene such as its extremely high room-temperature electron mobility and thermal conductivity make this material appealing for many electronic and sensor applications. The absence of the energy band-gap in graphene's electronic spectrum motivates investigation of graphene nano-ribbons in which the electronic "transport gap" regime can be achieved when the width of the nano-ribbons is sufficiently small. The exact physical origin of the "transport gap" and its dependence on the width and the shape of graphene edges are still the subjects of debates. Here we report the calculations of the electron transport in graphene nano-ribbons. The method used for this study is based on the non-equilibrium Greens function method and the density functional theory. We focus our analysis on the possibility to open the band gap, induce the gap states via defects and on controlling the electrical conductivity by the chemical and physical means. Specifically, we varied the width of the hydrogen saturated zigzag graphene nano-ribbon and studied its effect on the current-voltage characteristics. It has been observed that the width of the ribbons affects the current-voltage characteristics considerably. The transport properties of graphene nanoribbon such as Seebeck coefficient, Hall coefficient have been extracted from our calculations. Our results also show that the graphene zigzag nano-ribbons exhibit nonlinear behavior of the current-voltage characteristics owing to the overlapping of pi and pi* bands near the Fermi level. The obtained results are important for the proposed electronic and optoelectronic applications of graphene nano-ribbons.
    Keywords: graphene; graphene nanoribbon; density functional theory; ATK; Application; Seebeck coefficient; Hall coefficient;
    Area: graphene
    BibTeX: 
    @article{Goli2012,
  author = {Goli, Pradyumna},
  title = {Current-Voltage Characteristics of Graphene Nanoribbons in the Ballistic Transport Regime},
  journal = {Journal of Nanoelectronics and Optoelectronics},
  year = {2012},
  volume = {7},
  number = {4},
  pages = {381--385},
  doi = {http://dx.doi.org/10.1166/jno.2012.1315}
}
    Jason T. Haraldsen, Peter Wölfle & Alexander V. Balatsky Understanding the electric-field enhancement of the superconducting transition temperature for complex oxide interfaces

    [Abstract] [BibTeX]

    		 2012 Phys. Rev. B
    Vol. 85(13), 134501-     		 DOI  
    Abstract: We examine the enhancement of the interfacial superconductivity between LaAlO3 and SrTiO3 by an effective electric field. Through the breaking of inversion symmetry at the interface, we show that a term in the free energy, coupling the superfluid density and an electric field, can augment the superconductivity transition temperature. Microscopically, we show that an electric field can also produce changes in the carrier density by relating the measured capacitance to the density of states. Through the standard BCS (Bardeen, Cooper, and Schrieffer) weak-coupling interaction in bulk SrTiO3, we estimate the transition temperature.
    Keywords: ATK; Application; superconductivity; interfaces;
    Area: interfaces
    BibTeX: 
    @article{Haraldsen2012,
  author = {Haraldsen, Jason T. and Wölfle, Peter and Balatsky, Alexander V.},
  title = {Understanding the electric-field enhancement of the superconducting transition temperature for complex oxide interfaces},
  journal = {Phys. Rev. B},
  publisher = {American Physical Society},
  year = {2012},
  volume = {85},
  number = {13},
  pages = {134501--},
  doi = {http://dx.doi.org/10.1103/PhysRevB.85.134501}
}
    Ren Hua, Liang Wei, Zhao Peng & Liu De-Sheng Low Bias Negative Differential Resistance with Large Peak-to-Valley Ratio in a BDC60 Junction

    [Abstract] [BibTeX]

    		 2012 Chinese Physics Letters
    Vol. 29(7), 077301-     		 DOI URL 
    Abstract: Based on nonequilibrium Green's function method and density functional theory calculations, we investigate theoretically the electronic transport properties of 1,4-bis(fullero[c]pyrrolidinl-yï)benzene (BDC60). A low bias negative differential resistance with the peak-to-valley ratio as high as 305.41 is obtained. The observed negative differential resistance is explained in terms of the evolution of the transmission spectra, molecular projected self-consistent Hamiltonian states and molecular projected energy levels with applied bias.
    Keywords: ATK; Application; molecular electronics; fullerenes; transport-properties; carbon; conductance
    Area: molecular electronics; fullerenes
    BibTeX: 
    @article{Hua2012,
  author = {Hua, Ren and Wei, Liang and Peng, Zhao and De-Sheng, Liu},
  title = {Low Bias Negative Differential Resistance with Large Peak-to-Valley Ratio in a BDC60 Junction},
  journal = {Chinese Physics Letters},
  year = {2012},
  volume = {29},
  number = {7},
  pages = {077301--},
  url = {http://stacks.iop.org/0256-307X/29/i=7/a=077301},
  doi = {http://dx.doi.org/10.1088/0256-307X/29/7/077301}
}
    Neeraj K. Jaiswal, Pankaj Srivastava & A.S. Sengar Enhancing metallicity in zigzag graphene nanoribbons with adsorbed/substitutionally doped copper atoms

    [Abstract] [BibTeX]

    		 2012 Nanotechnology (IEEE-NANO), 2012 12th IEEE Conference on, 1-4  DOI  
    Abstract: Width dependent properties of Cu doped zigzag graphene nanoribbons (ZGNR) have been examined with density functional theory. We considered Cu as an adsorbed atom as well as a substitutional dopant (SD) at edge and the centre of ZGNR. It is revealed that adsorption and SD affect the stability of the ribbons in a different manner. Adsorption is energetically favorable whereas SD results in stronger binding of Cu atom with ZGNR. Edge is found as the preferred site for both types of Cu doping. The electronic property of ZGNR is effectively modified by the presence of Cu atoms and enhanced metallicity is observed in nanoribbons with substitutional Cu impurity. The observed high metallicity of Cu doped ZGNR is crucial particularly for the nanoelectronic interconnects.
    Keywords: ATK; Application; graphene; doping; interconnections; formation energy; binding energy; transmission spectra
    Area: graphene
    BibTeX: 
    @inproceedings{Jaiswal2012b,
  author = {Jaiswal, Neeraj K. and Srivastava, Pankaj and Sengar, A. S.},
  title = {Enhancing metallicity in zigzag graphene nanoribbons with adsorbed/substitutionally doped copper atoms},
  booktitle = {Nanotechnology (IEEE-NANO), 2012 12th IEEE Conference on},
  year = {2012},
  pages = {1--4},
  doi = {http://dx.doi.org/10.1109/NANO.2012.6321984}
}
    Satoshi Kaneko, Lu Wang, Guangfu Luo, Jing Lu, Shigeru Nagase, Satoru Sato, Michio Yamada, Zdenek Slanina, Takeshi Akasaka & Manabu Kiguchi Electron transport through single endohedral Ce@C_82 metallofullerenes

    [Abstract] [BibTeX]

    		 2012 Phys. Rev. B
    Vol. 86(15), 155406-     		 DOI  
    Abstract: The electron transport through a single endohedral Ce@C82 metallofullerene bridging between metal electrodes was investigated with experimental (break junction) as well as theoretical (density functional theory coupled with the nonequilibrium Green's function formalism) techniques. The single Ce@C82 molecule junction showing a high and fixed conductance value was fabricated by direct binding of the metallofullerene to Ag electrodes. The junction had a conductance of 0.28(±0.05)G0 (G0 = 2e2/h), which was much larger than that of single molecule junctions having anchoring groups (<0.01G0), but only half that of the single C60 molecule junction of 0.5G0. The unexpected reduced conductance of the single Ce@C82 molecule junction compared with that of the single C60 molecule junction was supported by the ab initio quantum transport calculations and was explained in terms of the localization of electrons in the C82 cage. In the case of the Au electrodes, the single Ce@C82 molecule junction was not formed by the break junction technique because the Ce@C82 molecule could not be trapped in the large Au nanogap, which was formed just after breaking the Au contacts.
    Keywords: ATK; Application; molecular electronics; fullerenes; molecular electronics; anchoring groups; conductance; density; chemistry; junctions; exchange; behavior
    Area: molecular electronics; fullerenes
    BibTeX: 
    @article{Kaneko2012,
  author = {Kaneko, Satoshi and Wang, Lu and Luo, Guangfu and Lu, Jing and Nagase, Shigeru and Sato, Satoru and Yamada, Michio and Slanina, Zdenek and Akasaka, Takeshi and Kiguchi, Manabu},
  title = {Electron transport through single endohedral Ce@C_82 metallofullerenes},
  journal = {Phys. Rev. B},
  publisher = {American Physical Society},
  year = {2012},
  volume = {86},
  number = {15},
  pages = {155406--},
  doi = {http://dx.doi.org/10.1103/PhysRevB.86.155406}
}
    Hong Seok Kang Spin-polarized transport through heterobilayers of graphene nanoribbons and ruthenium-porphyrin tapes

    [Abstract] [BibTeX]

    		 2012 Chemical Physics
    Vol. 405(0), 148-154     		 DOI  
    Abstract: Using the first-principles calculation, we have shown that armchair graphene nanoribbons (aGNR) exhibit highly spin-polarized transport by forming heterobilayers with one-dimensional ruthenium porphyrin tapes (Ru-PPTs). Due to stronger electronic coupling, the bilayer formation between aGNRs and doubly-linked (DL) Ru-PPTs is stronger than that between aGNRs and triply-linked (TL) Ru-PPTs. While the TL bilayer is a quasi-metal, the DL bilayer preserves the half-metallic character of the underlying DL Ru-PPT. At an applied bias of 0.1 V, the conductance of the DL heterobilayer is 99.7% spin-polarized.
    Keywords: first-principles calculation; armchair graphene nanoribbon; porphyrin tapes; heterobilayer; half-metal; conductance; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Kang2012,
  author = {Kang, Hong Seok},
  title = {Spin-polarized transport through heterobilayers of graphene nanoribbons and ruthenium-porphyrin tapes},
  journal = {Chemical Physics},
  year = {2012},
  volume = {405},
  number = {0},
  pages = {148--154},
  doi = {http://dx.doi.org/10.1016/j.chemphys.2012.07.001}
}
    Junya Koga, Yuta Tsuji & Kazunari Yoshizawa Orbital Control of Single-Molecule Conductance Perturbed by pi-Accepting Anchor Groups: Cyanide and Isocyanide

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(38)The Journal of Physical Chemistry C, 20607-20616     		 DOI  
    Abstract: Electron transport properties through benzene molecules disubstituted with pi-accepting cyanide and isocyanide anchor groups at their para and meta positions are investigated on the basis of a qualitative orbital analysis at the Hückel molecular orbital level of theory. The applicability of a previously derived orbital symmetry rule for electron transport is extended to the systems perturbed by the pi-accepting anchor groups, where the HOMO-LUMO symmetry in the molecular orbital energies relative to the Fermi level is removed. The conservation of the HOMO-LUMO symmetry in the spatial distribution of the molecular orbitals between the unperturbed benzene molecule and the perturbed molecules with the anchor groups rationalizes symmetry-allowed electron transport through the para isomers. On the other hand, destructive interferences between the nearly 2-fold degenerate frontier orbitals constructed from the 2-fold degenerate orbitals of the unperturbed benzene molecule and the anchor groups lead to symmetry-forbidden electron transport through the meta isomers. The qualitative orbital thinking is supported by more quantitative density functional theory (DFT) calculations combined with the nonequilibrium Green's function (NEGF) method. The orbital analysis is a powerful tool for the understanding and rational design of molecular devices composed of pi-conjugated hydrocarbons and those perturbed by the pi-accepting anchor groups.
    Keywords: ATK; Application; molecular electronics; nanosized graphite sheets; electron transport; quantum transport; contact resistance; tunneling current; charge transport; metal junctions; terminal groups; density; views
    Area: molecular electronics
    BibTeX: 
    @article{Koga2012,
  author = {Koga, Junya and Tsuji, Yuta and Yoshizawa, Kazunari},
  title = {Orbital Control of Single-Molecule Conductance Perturbed by pi-Accepting Anchor Groups: Cyanide and Isocyanide},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {38},
  pages = {20607--20616},
  doi = {http://dx.doi.org/10.1021/jp3068156}
}
    Xingxing Li, Xiaojun Wu, Zhenyu Li, Jinlong Yang & J.G. Hou Bipolar magnetic semiconductors: a new class of spintronics materials

    [Abstract] [BibTeX]

    		 2012 Nanoscale
    Vol. 4(18), 5680-5685     		 DOI  
    Abstract: Electrical control of spin polarization is very desirable in spintronics, since electric fields can be easily applied locally, in contrast to magnetic fields. Here, we propose a new concept of bipolar magnetic semiconductors (BMS) in which completely spin-polarized currents with reversible spin polarization can be created and controlled simply by applying a gate voltage. This is a result of the unique electronic structure of BMS, where the valence and conduction bands possess opposite spin polarization when approaching the Fermi level. BMS is thus expected to have potential for various applications. Our band structure and spin-polarized electronic transport calculations on semi-hydrogenated single-walled carbon nanotubes confirm the existence of BMS materials and demonstrate the electrical control of spin-polarization in them.
    Keywords: ATK; Application; molecular electronics; spin; magnetism; nanotube; electron-spin; carbon nanotubes; ferromagnetism; magnetoresistance; nanostructures; manipulation; transition; transport; exchange; fields
    Area: nanotubes; spin; semi
    BibTeX: 
    @article{Li2012k,
  author = {Li, Xingxing and Wu, Xiaojun and Li, Zhenyu and Yang, Jinlong and Hou, J. G.},
  title = {Bipolar magnetic semiconductors: a new class of spintronics materials},
  journal = {Nanoscale},
  publisher = {The Royal Society of Chemistry},
  year = {2012},
  volume = {4},
  number = {18},
  pages = {5680--5685},
  doi = {http://dx.doi.org/10.1039/C2NR31743E}
}
    Ahmed Mahmoud & Paolo Lugli Transport characterization of a gated molecular device with negative differential resistance

    [Abstract] [BibTeX]

    		 2012 Nanotechnology (IEEE-NANO), 2012 12th IEEE Conference on, 1-5  DOI  
    Abstract: Due to increasing demand for advances in minimization, power consumption and speed of electronic devices, new technologies are emerging in order to replace/support the current semiconductor technology. Molecular electronics is one of the promising technologies that can offer an extreme increase in the integration density, since single molecules could be employed as active electronic devices. This theoretical paper deals with the transport characteristics of a gated molecular device, employing dithiolated Oligo-Phenylene Vinylene (OPV) molecules as testbed. The output current curves show a gate voltage dependency. In addition, a negative differential resistance (NDR) is observed. Transmission spectra, charge density distributions and potential profiles of the molecular device are provided to explain of the gate dependency and NDR behavior.
    Keywords: ATK-SE; Application; molecular devices; negative differential; resistance; oligo-phenylene vinylene; NEGF; molecular electronics; negative differential resistance; NDR
    Area: molecular electronics
    BibTeX: 
    @inproceedings{Mahmoud2012,
  author = {Mahmoud, Ahmed and Lugli, Paolo},
  title = {Transport characterization of a gated molecular device with negative differential resistance},
  booktitle = {Nanotechnology (IEEE-NANO), 2012 12th IEEE Conference on},
  year = {2012},
  pages = {1--5},
  doi = {http://dx.doi.org/10.1109/NANO.2012.6321941}
}
    L. Pan, H.J. Liu, X.J. Tan, H.Y. Lv, J. Shi, X.F. Tang & G. Zheng Thermoelectric properties of armchair and zigzag silicene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Phys. Chem. Chem. Phys.
    Vol. 14(39), 13588-13593     		 DOI  
    Abstract: Using the nonequilibrium Green's function method and nonequilibrium molecular dynamics simulations, we discuss the possibility of using silicene nanoribbons (SiNRs) as high performance thermoelectric materials. It is found that SiNRs are structurally stable if the edge atoms are passivated by hydrogen, and those with armchair edges usually exhibit much better thermoelectric performance than their zigzag counterparts. The room temperature ZT value of armchair SiNRs shows a width-dependent oscillating decay, while it decreases slowly with increasing ribbon width for the zigzag SiNRs. In addition, there is a strong temperature dependence of the thermoelectric performance of these SiNRs. Our theoretical calculations indicate that by optimizing the doping level and applied temperature, the ZT value of SiNRs could be enhanced to as high as 4.9 which suggests their very appealing thermoelectric applications.
    Keywords: ATK; Application; silicene nanoribbon; thermoelectric properties; ZT; Seebeck coefficient; ab initio molecular dynamics; nanowires; figure of merit; performance; simulation; nanotubes; systems; metals
    Area: semi; thermo
    BibTeX: 
    @article{Pan2012,
  author = {Pan, L. and Liu, H. J. and Tan, X. J. and Lv, H. Y. and Shi, J. and Tang, X. F. and Zheng, G.},
  title = {Thermoelectric properties of armchair and zigzag silicene nanoribbons},
  journal = {Phys. Chem. Chem. Phys.},
  publisher = {The Royal Society of Chemistry},
  year = {2012},
  volume = {14},
  number = {39},
  pages = {13588--13593},
  doi = {http://dx.doi.org/10.1039/C2CP42645E}
}
    Sweta Parashar, Pankaj Srivastava & Manisha Pattanaik First-principles study of naphthalene-based single-electron transistor

    [Abstract] [BibTeX]

    		 2012 Applied Nanoscience
    Vol. 2(3), 385-388     		 DOI  
    Abstract: We have performed first-principle calculations based on density functional theory (DFT) and non-equilibrium greens functions (NEGF) for calculating the charging energies of molecular system weakly coupled to an environment. We apply this approach to the molecule naphthalene, which is lying flat on gate dielectric between the source and drain electrodes. Our calculated values of charging energy for naphthalene in an isolated case are in good agreement with experimental values. Further, in an electrostatic environment, the result shows renormalization of molecular energy levels and therefore reduces the charging energy of naphthalene. Subsequently, the charge stability diagram of naphthalene based single-electron transistor (SET) has been obtained by calculating the charging energies as a function of an external gate potential. This diagram shows the dependence of SET conductance on the gate voltage and the source-drain bias. Our implementation is intended to predict the charging energies of the naphthalene-based SETs that reveals further scope in realization of the devices at nanoscale.
    Keywords: single-electron transistor; charging energy; ionization energy; electron affinity; charge stability diagram; ATK; Application
    Area: SET
    BibTeX: 
    @article{Parashar2012,
  author = {Parashar, Sweta and Srivastava, Pankaj and Pattanaik, Manisha},
  title = {First-principles study of naphthalene-based single-electron transistor},
  journal = {Applied Nanoscience},
  publisher = {Springer Berlin / Heidelberg},
  year = {2012},
  volume = {2},
  number = {3},
  pages = {385--388},
  doi = {http://dx.doi.org/10.1007/s13204-012-0112-x}
}
    Lei Shen, Minggang Zeng, Suchun Li, Michael B. Sullivan & Yuan Ping Feng Electron transmission modes in electrically biased graphene nanoribbons and their effects on device performance

    [Abstract] [BibTeX]

    		 2012 Phys. Rev. B
    Vol. 86(11), 115419-     		 DOI  
    Abstract: Using ab initio transport methods, we investigate electron transmission modes (channels, pathways, and intensities) in electrically biased graphene nanoribbons (GNRs) under different growth conditions. In addition to the bond currents, we report loop currents in such devices, induced by the electrons hopping between carbon atoms of the same sublattice under bias. The loop current channel as well as the bond current channel play an important role in the local current in electrically biased GNR-based devices. The effect of edge functional groups and surface defects/groups on device performance depends on the current pathway and intensity in these two channels. Understanding the details of local currents in GNRs paves the way to make high-performance GNR-based electronic devices, such as GNR field effect transistors.
    Keywords: ATK; Application; graphene nanoribbon; field effect transistors; FET; carbon nanotubes; transistors; magnetoresistance; transport; defects; edges
    Area: graphene
    BibTeX: 
    @article{Shen2012a,
  author = {Shen, Lei and Zeng, Minggang and Li, Suchun and Sullivan, Michael B. and Feng, Yuan Ping},
  title = {Electron transmission modes in electrically biased graphene nanoribbons and their effects on device performance},
  journal = {Phys. Rev. B},
  publisher = {American Physical Society},
  year = {2012},
  volume = {86},
  number = {11},
  pages = {115419--},
  doi = {http://dx.doi.org/10.1103/PhysRevB.86.115419}
}
    Anurag Srivastava & Neha Tyagi Pressure-induced phase transition in Ga 1-x In x As: ab initio study

    [Abstract] [BibTeX]

    		 2012 High Pressure Research
    Vol. 32(2)High Pressure Research, 299-308     		 DOI  
    Abstract: The high pressure phase transitions in Ga 1-x In x As (x=0.25, 0.5 and 0.75) alloys have been investigated using the ab initio density functional theory approach. The total energies and ground state properties have been analyzed using both the local density as well as generalized gradient approximations as exchange-correlation functionals. The study computes the structural phase transition in Ga 1-x In x As from its most stable zinc-blende- (B3) type phase to hypothetical rocksalt- (B1) type phase in the pressure range of 3-14 GPa. The observed transition pressures for the host binary compounds are in close agreement with their experimental/theoretical counterparts. The effect of introduction of indium in GaAs has also been analyzed on the lattice parameter, bulk modulus and transition pressure.
    Keywords: ab initio; phase transition; high pressure; GaAs; InAs; III-V; alloys; ATK; Application
    Area: semi
    BibTeX: 
    @article{Srivastava2012c,
  author = {Srivastava, Anurag and Tyagi, Neha},
  title = {Pressure-induced phase transition in Ga 1-x In x As: ab initio study},
  booktitle = {High Pressure Research},
  journal = {High Pressure Research},
  publisher = {Taylor & Francis},
  year = {2012},
  volume = {32},
  number = {2},
  pages = {299--308},
  doi = {http://dx.doi.org/10.1080/08957959.2012.686613}
}
    Anurag Srivastava & Neha Tyagi Pressure-induced phase transition and electronic properties of AlN nanowires: an ab initio study

    [Abstract] [BibTeX]

    		 2012 Phase TransitionsPhase Transitions, 1-13  DOI URL 
    Abstract: The structural stability of AlN nanowires have been analyzed in wurtzite (B4), zincblende (B3), rocksalt (B1) and CsCl (B2) type phases using density functional theory based ab initio approach. The total energy calculations have been performed in a self-consistent manner using local density approximation as exchange correlation functional. The analysis finds the B4 type phase as most stable amongst the other phases taken into consideration and observes the structural phase transition from B4>B3, B4>B1, B4>B2, B3>B1 and B3>B2 at 42.7, 76.54, 142, 30.4 and 108.9 GPa respectively. Lattice parameter, bulk modulus and pressure derivatives of AlN nanowires have also been calculated for all the stable phases. The electronic band structure analysis of AlN nanowires shows a semiconducting nature in its B4, B3 and B1 type phases, whereas the B2 type phase is found to be metallic.
    Keywords: AlN; nanowires; phase transition; electronic properties; ab initio; ATK; Application
    Area: semi
    BibTeX: 
    @article{Srivastava2012d,
  author = {Srivastava, Anurag and Tyagi, Neha},
  title = {Pressure-induced phase transition and electronic properties of AlN nanowires: an ab initio study},
  booktitle = {Phase Transitions},
  journal = {Phase Transitions},
  publisher = {Taylor & Francis},
  year = {2012},
  pages = {1--13},
  url = {http://www.tandfonline.com/doi/abs/10.1080/01411594.2012.693611},
  doi = {http://dx.doi.org/10.1080/01411594.2012.693611}
}
    Anurag Srivastava, Arpit Jain, Rajnish Kurchania & Neha Tyagi Width Dependent Electronic Properties of Graphene Nanoribbons: An Ab-Initio Study

    [Abstract] [BibTeX]

    		 2012 Journal of Computational and Theoretical Nanoscience
    Vol. 9(7), 1008-1013     		 DOI  
    Abstract: We have analyzed the electronic properties of armchair and zigzag shaped graphene nanoribbons (GNRs) using density functional theory based ab-initio approach. The present computation employs the Perdew Zunger (PZ) type parameterized local density approximation (LDA) and revised Perdew Burke Ernzerhof (RPBE) type generalized gradient approximation (GGA) as exchange correlation functional. The calculated electronic band gap and density of states shows a close match with its other theoretical counterparts. In another observation, we have found a non linear variation of GNRs energy bandgap as a function of width.
    Keywords: ATK; Application; graphene nanoribbons; DFT; electronic properties; energy band gap; generalized gradient approximation; bilayer graphene; doped graphene; transparent; films
    Area: graphene
    BibTeX: 
    @article{Srivastava2012e,
  author = {Srivastava, Anurag and Jain, Arpit and Kurchania, Rajnish and Tyagi, Neha},
  title = {Width Dependent Electronic Properties of Graphene Nanoribbons: An Ab-Initio Study},
  journal = {Journal of Computational and Theoretical Nanoscience},
  year = {2012},
  volume = {9},
  number = {7},
  pages = {1008--1013},
  doi = {http://dx.doi.org/10.1166/jctn.2012.2133}
}
    Aleksandar Staykov, Xinqian Li, Yuta Tsuji & Kazunari Yoshizawa Current Rectification in Nitrogen- and Boron-Doped Nanographenes and Cyclophanes

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(34)The Journal of Physical Chemistry C, 18451-18459     		 DOI  
    Abstract: Electron transport properties of boron- and nitrogen-doped polycyclic aromatic hydrocarbons and cyclophanes are investigated with the nonequilibrium Green's function method and compared to transport properties of the unsubstituted species. The aim of the study is to derive the effect of the heteroatomic defects on the conductance of nanographenes and to propose new effective ways for current control and design of carbon devices. Of special interest are the electrical current rectifying properties of asymmetrically doped nanographenes and cyclophanes, as well as the rectification mechanism. The mechanisms of donor-pi bridge-acceptor and donor-pi bridge-acceptor rectification are used to explain the diode-like properties of asymmetrically doped nanographenes and cyclophanes. The electron-rich nitrogen and electron-poor boron heteroatoms introduce conductance channels within the highest occupied molecular orbital/lowest unoccupied molecular orbital gaps of the hydrocarbons and cyclophanes and significantly enhance the conductance. The combination of nitrogen and boron impurities in one polycyclic aromatic hydrocarbon leads to asymmetrical I/V curves. The rectification is further enhanced in the cyclophanes where the boron impurities are located in one of the layers and the nitrogen impurities in the other. Owing to the efficient separation of the donor and acceptor parts, a higher rectification ratio is estimated. The rectifying properties of the asymmetrically doped carbon materials are derived from the nonequilibrium Green's function theory. The main reason for the rectification is found to be the interaction of the external electric field induced between the electrodes with the molecular orbitals of the asymmetrically doped hydrocarbons.
    Keywords: molecular electronics; ATK; Application; doping; nanographenes; rectification;
    Area: molecular electronics
    BibTeX: 
    @article{Staykov2012,
  author = {Staykov, Aleksandar and Li, Xinqian and Tsuji, Yuta and Yoshizawa, Kazunari},
  title = {Current Rectification in Nitrogen- and Boron-Doped Nanographenes and Cyclophanes},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {34},
  pages = {18451--18459},
  doi = {http://dx.doi.org/10.1021/jp303843k}
}
    K. Tang, Z. Ni, Q. Liu, R. Quhe, Q. Zheng, J. Zheng, R. Fei, Z. Gao & J. Lu Electronic and transport properties of a biased multilayer hexagonal boron nitride

    [Abstract] [BibTeX]

    		 2012 The European Physical Journal B - Condensed Matter and Complex Systems
    Vol. 85(9), 301     		 DOI  
    Abstract: We explore the electronic and transport properties out of a biased multilayer hexagonal boron nitride (h-BN) by first-principles calculations. The band gaps of multilayer h-BN decrease almost linearly with increasing perpendicular electric field, irrespective of the layer number N and stacking manner. The critical electric filed ( E 0 ) required to close the band gap decreases with the increasing N and can be approximated by E 0 = 3.2/(N-1) (eV). We provide a quantum transport simulation of a dual-gated 4-layer h-BN with graphene electrodes. The transmission gap in this device can be effectively reduced by double gates, and a high on-off ratio of 3000 is obtained with relatively low voltage. This renders biased MLh-BN a promising channel in field effect transistor fabrication.
    Keywords: ATK; Application; graphane; field-effect transistor; FET; hexagonal boron-nitride; bilayer graphene; bandgap
    Area: graphene
    BibTeX: 
    @article{Tang2012a,
  author = {Tang, K. and Ni, Z. and Liu, Q. and Quhe, R. and Zheng, Q. and Zheng, J. and Fei, R. and Gao, Z. and Lu, J.},
  title = {Electronic and transport properties of a biased multilayer hexagonal boron nitride},
  journal = {The European Physical Journal B - Condensed Matter and Complex Systems},
  publisher = {Springer Berlin / Heidelberg},
  year = {2012},
  volume = {85},
  number = {9},
  pages = {301},
  doi = {http://dx.doi.org/10.1140/epjb/e2012-30236-6}
}
    Yangyang Wang, Jiaxin Zheng, Zeyuan Ni, Ruixiang Fei, Qihang Liu, Ruge Quhe, Chengyong Xu, Jing Zhou, Zhengxiang Gao & Jing Lu Half-metallic Silicene And Germanene Nanoribbons: Towards High-performance Spintronics Device

    [Abstract] [BibTeX]

    		 2012 NANO
    Vol. 7(5)Nano, 1250037-     		 DOI  
    Abstract: By using first-principles calculations, we predict that an in-plane homogenous electrical field can induce half-metallicity in hydrogen-terminated zigzag silicene and germanene nanoribbons (ZSiNRs and ZGeNRs). A dual-gated finite ZSiNR device reveals a nearly perfect spin-filter efficiency (SFE) of up to 99% while a quadruple-gated finite ZSiNR device serves as an effective spin field effect transistor (FET) with an on/off current ratio of over 100 from ab initio quantum transport simulation. This discovery opens up novel prospect of silicene and germanene in spintronics.
    Keywords: ATK; Application; silicene nanoribbon; germanene nanoribbon; half-metallicity; spin-filter; spin field effect transistor; first-principles calculation; graphene nanoribbons; spin transport; transistors; magnetoresistance; molecules
    Area: semi; spin
    BibTeX: 
    @article{Wang2012b,
  author = {Wang, Yangyang and Zheng, Jiaxin and Ni, Zeyuan and Fei, Ruixiang and Liu, Qihang and Quhe, Ruge and Xu, Chengyong and Zhou, Jing and Gao, Zhengxiang and Lu, Jing},
  title = {Half-metallic Silicene And Germanene Nanoribbons: Towards High-performance Spintronics Device},
  booktitle = {Nano},
  journal = {NANO},
  publisher = {World Scientific Publishing Co.},
  year = {2012},
  volume = {7},
  number = {5},
  pages = {1250037--},
  doi = {http://dx.doi.org/10.1142/S1793292012500373}
}
    X.Z. Wu, M.Q. Long, L.N. Chen, C. Cao, S.S. Ma & H. Xu The effects of side groups on the electronic transport properties of carbon chain molecular devices

    [Abstract] [BibTeX]

    		 2012 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 45(0), 82-85     		 DOI  
    Abstract: Applying nonequilibrium Green's functions in combination with the density functional theory, we investigated the effect of amino and hydroxyl groups on the transport property of the carbon atomic chains. The results show the conductance oscillation with the length and the parity of the carbon atomic chains, and the electronic transport properties can be modulated by the sites of amino and hydroxyl groups. And also, the negative differential resistance behaviors can be observed clearly. These phenomena may originate from the interaction of side groups with the carbon atomic chains and the change in coupling degree between the molecular orbitals and electrode states.
    Keywords: ATK; Application; molecular electronics; atomic chain; conductance
    Area: molecular electronics
    BibTeX: 
    @article{Wu2012b,
  author = {Wu, X.Z. and Long, M.Q. and Chen, L.N. and Cao, C. and Ma, S.S. and Xu, H.},
  title = {The effects of side groups on the electronic transport properties of carbon chain molecular devices},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2012},
  volume = {45},
  number = {0},
  pages = {82--85},
  doi = {http://dx.doi.org/10.1016/j.physe.2012.07.011}
}
    Ting-Ting Wu, Xue-Feng Wang, Yongjing Jiang & Liping Zhou Spin Transport in Be Edge-Doped Graphene Nanoribbon

    [Abstract] [BibTeX]

    		 2012 Journal of Nanoscience and Nanotechnology
    Vol. 12(8), 6467-6471     		 DOI  
    Abstract: We report an atomistic simulation of spin dependent charge transport in zigzag graphene nanoribbons with 4 zigzag chains doped by a Beryllium atom on one edge. The spin dependent density functional theory with norm-conserving atomic basis set is employed to describe the system and the current versus voltage behavior is calculated by the nonequilibrium Green's function method for quantum transport. The Be impurity atom suppresses the local magnetization near the edge and the transmitted charge current becomes spin polarized accordingly. Both spin-up and spin-down transmission spectra are modified significantly but in different ways. Distinguished from the previous doping results of other impurity elements, here we observe negative differential resistance for only one of the spins in the nonlinear transport regime below bias 1.5 V. Molecular projected Hamiltonian energy spectrum near the impurity shows that the impurity removes the energy degeneracy of spin in perfect ribbon. The current versus voltage shows semiconductor behavior with fluctuating spin polarization of amplitude up to 37%
    Keywords: ATK; Application; doping; spin transport; graphene nanoribbon; negative differential resistance; NDR; defects
    Area: graphene; spin
    BibTeX: 
    @article{Wu2012c,
  author = {Wu, Ting-Ting and Wang, Xue-Feng and Jiang, Yongjing and Zhou, Liping},
  title = {Spin Transport in Be Edge-Doped Graphene Nanoribbon},
  journal = {Journal of Nanoscience and Nanotechnology},
  year = {2012},
  volume = {12},
  number = {8},
  pages = {6467--6471},
  doi = {http://dx.doi.org/10.1166/jnn.2012.5440}
}
    Jian-Fei Yang, Liping Zhou, Qin Han & Xue-Feng Wang Bias-Controlled Giant Magnetoresistance through Cyclopentadienyl-Iron Multidecker Molecules

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(37)The Journal of Physical Chemistry C, 19996-20001     		 DOI  
    Abstract: We investigated giant magnetoresistance (GMR) across cyclopentadienyl-iron multidecker molecules [Fe_m(C5H5)_n] using the density functional theory and nonequilibrium Green's function techniques. An oscillation behavior of the molecular magnetic moments was observed. Spin-polarized transport calculations through the lead-multidecker molecule-lead junctions predicted large bias-controlled magnetoresistive response, with the highest GMR ratio up to 2.0*10^4%. The positive to negative conversion of the GMR values was also observed with bias change. The transmission spectra and eigenvalues of the molecular junctions were calculated to understand the mechanism of spin transport in these systems. Various ways to manipulate the GMR behavior are illustrated, opening up prospects of new molecular spintronic devices.
    Keywords: ATK; Application; molecular electronics; giant magnetoresistance; sandwich clusters; spin transport; benzene; wires; ferromagnetism; spintronics; metals
    Area: molecular electronics; spin;
    BibTeX: 
    @article{Yang2012,
  author = {Yang, Jian-Fei and Zhou, Liping and Han, Qin and Wang, Xue-Feng},
  title = {Bias-Controlled Giant Magnetoresistance through Cyclopentadienyl-Iron Multidecker Molecules},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {37},
  pages = {19996--20001},
  doi = {http://dx.doi.org/10.1021/jp300465e}
}
    Zhi Yang, Shaoding Liu, Xuguang Liu, Yongzhen Yang, Xiuyan Li, Shijie Xiong & Bingshe Xu The spin-filter capability and spin-reversal effect of multidecker iron-borazine sandwich cluster

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 101(10), 102405     		 DOI  
    Abstract: Using density functional theory and non-equilibrium Green's function technique, we performed theoretical investigations on the magnetic and transport properties of Fe_n(B3N3H6)_(n+1) (n=1-4) sandwich clusters. The calculated results show that the clusters possess high magnetic moments owing to the unpaired d_delta electrons. Furthermore, high spin-filter capability, negative differential resistance, and spin-reversal effect were found in the systems, and the possible physical origination of the phenomena was suggested. Our findings also indicate that the magnetic or electrical properties of the system could be controlled by cluster size, and these sandwich clusters are promising materials for application in molecular electronics or spintronics.
    Keywords: ATK; Application; density functional theory; electrical resistivity; gold; Green's function methods; iron compounds; magnetic moments; M-I-M; MIM; sandwich structures; molecular wires; transport; magnetism
    Area: molecular electronics; spin
    BibTeX: 
    @article{Yang2012a,
  author = {Yang, Zhi and Liu, Shaoding and Liu, Xuguang and Yang, Yongzhen and Li, Xiuyan and Xiong, Shijie and Xu, Bingshe},
  title = {The spin-filter capability and spin-reversal effect of multidecker iron-borazine sandwich cluster},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {101},
  number = {10},
  pages = {102405},
  doi = {http://dx.doi.org/10.1063/1.4751340}
}
    Jun You, Jun He, Ming-Ming Yin, Li-Ming Tang, Ke-Qiu Chen & Zhi-Qiang Fan The E-Z photo-isomerization switching behavior in single molecular device with carbon nanotube electrodes

    [Abstract] [BibTeX]

    		 2012 Computational Materials Science
    Vol. 65(0), 203-206     		 DOI  
    Abstract: By using nonequilibrium Green's functions in combination with the density-functional theory, we investigate the electronic transport properties of the molecular device constructed by a single 4,4-(ethene-1,2-diyl) dibenzoic acid sandwiched between carbon nanotube electrodes. The results show that an obvious reversible switching behavior can be observed when the molecular structure changes between E isomerization and Z isomerization by ultraviolet irradiation or visible irradiation. More importantly, the switching ratio can reach to a maximum (about 7000) at 0.28 V and then decrease gradually to a minimum at 0.48 V. It is suggested that the controllable switching behavior is very useful for the design of functional molecular devices.
    Keywords: electronic transport; single molecular device; switching behavior; nanotube; ATK; Application; switching; rectification
    Area: molecular electronics
    BibTeX: 
    @article{You2012,
  author = {You, Jun and He, Jun and Yin, Ming-Ming and Tang, Li-Ming and Chen, Ke-Qiu and Fan, Zhi-Qiang},
  title = {The E-Z photo-isomerization switching behavior in single molecular device with carbon nanotube electrodes},
  journal = {Computational Materials Science},
  year = {2012},
  volume = {65},
  number = {0},
  pages = {203--206},
  doi = {http://dx.doi.org/10.1016/j.commatsci.2012.07.022}
}
    C.X. Zhang, Chaoyu He, Lin Xue, K.W. Zhang, L.Z. Sun & Jianxin Zhong Transport properties of zigzag graphene nanoribbons with oxygen edge decoration

    [Abstract] [BibTeX]

    		 2012 Organic Electronics
    Vol. 13(11), 2494-2501     		 DOI  
    Abstract: Using the density functional theory in combination with the nonequilibrium Green's function method, we investigate the transport properties of zigzag-edged graphene nanoribbons (ZGNRs) with oxygen edge decoration (passivated by the ketone (C=O) or ether (C-O-C), denoting as ZGNR-CO and ZGNR-C2O, respectively). We find that both ZGNR-CO and ZGNR-C2O induce the semiconductor-metal transition and enhance the transmission conductance within "transparent" electrodes. However, sandwiched by Au (111) electrodes, Au|ZGNR - CO|Au enhances the transport properties while Au|ZGNR - C2O|Au depresses the transport properties in comparison with Au|ZGNR - H|Au. It is found that the transport properties of the edge oxidized ZGNRs within Au (111) electrodes depend on the electronic states around the Fermi level which determine the number of the effective transport channels. The states of Au|ZGNR - CO|Au are delocalized on the edge oxygen atoms as well as the inner edge carbon atoms, introducing extra transport channels. Moreover, in comparison with Au|ZGNR - H|Au, the effective transport channels of Au|ZGNR - CO|Au increase at given applied bias. However, the states of Au|ZGNR - C2O|Au are localized on the ribbon, blocking the effective transport channels.
    Keywords: zigzag-edged graphene nanoribbons; edge oxidization; transport properties; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Zhang2012e,
  author = {Zhang, C.X. and He, Chaoyu and Xue, Lin and Zhang, K.W. and Sun, L.Z. and Zhong, Jianxin},
  title = {Transport properties of zigzag graphene nanoribbons with oxygen edge decoration},
  journal = {Organic Electronics},
  year = {2012},
  volume = {13},
  number = {11},
  pages = {2494--2501},
  doi = {http://dx.doi.org/10.1016/j.orgel.2012.06.041}
}
    Jiming Zheng, Ping Guo, Zhaoyu Ren, Zhenyi Jiang, Jintao Bai & Zhiyong Zhang Conductance fluctuations as a function of sliding motion in bilayer graphene nanoribbon junction: A first-principles investigation

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 101(8), 083101     		 DOI  
    Abstract: A bilayer graphene nanoribbon based strain sensor is designed and investigated via first principles simulations. The interlayer sliding induces dramatically oscillation of current in order of several magnitudes. Electronic structure analysis attributes this oscillation of current to periodic variation of HOMO-LUMO gap which comes from the periodic change of interlayer stacking configuration. This kind of behaviors could potentially be implemented in future strain sensor and other nanoelectronic devices.
    Keywords: ATK; Application; ab initio calculations; current fluctuations; electric admittance; electronic structure; graphene; molecular electronics; nanoelectronics; nanostructured materials
    Area: graphene
    BibTeX: 
    @article{Zheng2012b,
  author = {Zheng, Jiming and Guo, Ping and Ren, Zhaoyu and Jiang, Zhenyi and Bai, Jintao and Zhang, Zhiyong},
  title = {Conductance fluctuations as a function of sliding motion in bilayer graphene nanoribbon junction: A first-principles investigation},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {101},
  number = {8},
  pages = {083101},
  doi = {http://dx.doi.org/10.1063/1.4739838}
}
    X.H. Zheng, J. Lan, X.L. Wang, L.F. Huang, H. Hao & Z. Zeng Orbital symmetry induced conductance switching in a graphene nanoribbon heterojunction with different edge hydrogenations

    [Abstract] [BibTeX]

    		 2012 Appl. Phys. Lett.
    Vol. 101(5), 053101-4     		 DOI  
    Abstract: First principles calculations are performed to investigate the electron transport through a zigzag-edged graphene nanoribbon (ZGNR) heterojunction constructed by connecting a monohydrogenated ZGNR and a dihydrogenated ZGNR and its response to external magnetic fields. It is found that the heterojunction can be switched between a conducting state and an insulating state by tuning the magnetic fields. It arises from the matching or mismatching between the pi or pi* states of the two ribbons under different magnetic fields. This mechanism of conductance switching by tuning the orbital symmetry can be considered in the future design of graphene based electronic devices.
    Keywords: ATK; Application; ab initio calculations; electrical conductivity transitions; graphene; hydrogenation; nanoribbons; tuning; spin; half-metallicity; ribbons; stability
    Area: graphene; spin
    BibTeX: 
    @article{Zheng2012c,
  author = {Zheng, X. H. and Lan, J. and Wang, X. L. and Huang, L. F. and Hao, H. and Zeng, Z.},
  title = {Orbital symmetry induced conductance switching in a graphene nanoribbon heterojunction with different edge hydrogenations},
  journal = {Appl. Phys. Lett.},
  publisher = {AIP},
  year = {2012},
  volume = {101},
  number = {5},
  pages = {053101--4},
  doi = {http://dx.doi.org/10.1063/1.4739938}
}
    Fan Zhi-Qiang, Zhang Zhen-Hua, Qiu Ming, Deng Xiao-Qing & Tang Gui-Ping Controllable Negative Differential Resistance Behavior of an Azobenzene Molecular Device Induced by Different Molecule-Electrode Distances

    [Abstract] [BibTeX]

    		 2012 Chinese Physics Letters
    Vol. 29(7), 077305-     		 DOI URL 
    Abstract: Abstract: We report the ab initio calculations of transport behaviors of an azobenzene molecular device which is similar to the experimental configurations. The calculated results show that the transport behaviors of the device are sensitive to the molecule-electrode distance and the currents will drop rapidly when the molecule-electrode distance changes from 1.7 Å to 2.0 Å. More interestingly, the negative differential resistance behavior can be found in our device. Nevertheless, it is not the inherent property of an azobenzene molecular device but an effect of the molecule-electrode distance. Detailed analyses of the molecular projected self-consistent Hamiltonian states and the transmission spectra of the system reveal the physical mechanism of these behaviors.
    Keywords: ATK; Application; molecular electronics; MPSH analysis
    Area: molecular electronics
    BibTeX: 
    @article{Zhi-Qiang2012,
  author = {Zhi-Qiang, Fan and Zhen-Hua, Zhang and Ming, Qiu and Xiao-Qing, Deng and Gui-Ping, Tang},
  title = {Controllable Negative Differential Resistance Behavior of an Azobenzene Molecular Device Induced by Different Molecule-Electrode Distances},
  journal = {Chinese Physics Letters},
  year = {2012},
  volume = {29},
  number = {7},
  pages = {077305--},
  url = {http://stacks.iop.org/0256-307X/29/i=7/a=077305},
  doi = {http://dx.doi.org/10.1088/0256-307X/29/7/077305}
}
    Li-Ping An & Nian hua Liu The spin-dependent transport properties of zigzag graphene nanoribbon edge-defect junction

    [Abstract] [BibTeX]

    		 2012 New Carbon Materials
    Vol. 27(3), 181-187     		 DOI  
    Abstract: First-principles calculation was performed to investigate the transport properties of edge-defect junctions of graphene with H-terminated or bare edges, which were generated by removing edge carbon atoms from a perfect ribbon. The edge defect changes the electronic transport behavior of a zigzag graphene nanoribbon from spin-degenerated for a perfect ribbon to highly spin-polarized for edge-defective ones at the Fermi level. The electronic local density of states isosurface calculations could help understand the transport results. These junctions could generate spin-polarized currents. Especially, the bare edge-defect junction has a high spin filter efficiency regardless of the external bias. This behavior suggests a possible use of the edge-defective graphene in a spin filter system.
    Keywords: graphene nanoribbon; edge-defect junction; spin-dependent transport; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{An2012b,
  author = {An, Li-Ping and Liu, Nian-hua},
  title = {The spin-dependent transport properties of zigzag graphene nanoribbon edge-defect junction},
  journal = {New Carbon Materials},
  year = {2012},
  volume = {27},
  number = {3},
  pages = {181--187},
  doi = {http://dx.doi.org/10.1016/S1872-5805(12)60012-2}
}
    Can Cao, Ling-Na Chen, Meng-Qiu Long, Wei-Rong Huang & Hui Xu Electronic transport properties on transition-metal terminated zigzag graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Journal of Applied Physics
    Vol. 111(11), 113708     		 DOI  
    Abstract: By using non-equilibrium Green's functions in combination with the density-functional theory, we investigate the spin transport properties of molecular junctions based on 3d transition terminated zigzag graphene nanoribbons. The results show that the electronic transport properties are strongly depending on the type of terminated atom at the edge of ribbon. The currents of spin-up and spin-down display different behaviors, and the spin-filter effects can be observed. These unconventional doping effects could be used to design novel nanospintronics devices.
    Keywords: density functional theory; doping; Fermi level; graphene; Green's function methods; nanoribbons; spin polarised transport; ATK; Application
    Area: graphene spin
    BibTeX: 
    @article{Cao2012b,
  author = {Can Cao and Ling-Na Chen and Meng-Qiu Long and Wei-Rong Huang and Hui Xu},
  title = {Electronic transport properties on transition-metal terminated zigzag graphene nanoribbons},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2012},
  volume = {111},
  number = {11},
  pages = {113708},
  doi = {http://dx.doi.org/10.1063/1.4723832}
}
    M. Chakraverty & H.M. Kittur Evidence of hysteresis from first principle DFT simulations of I-V curves in Pt/TiO(2-x) - TiO2/Pt memristive systems

    [Abstract] [BibTeX]

    		 2012 Devices, Circuits and Systems (ICDCS), 2012 International Conference on, 379-383  DOI  
    Abstract: The memristor is an electrical circuit element that is similar to a resistor but has the potential to maintain state between turning power on and off. These memristors are about half the size of the transistors found in current flash storage technology, allowing capacity of these devices to double. This paper discusses the basics of memristors, which is an electrical circuit element, and presents the first principle simulation results of Pt/TiO2-x - TiO2/Pt system where the central region has a boundary separating TiO2-x and TiO2 regions. This barrier is progressively shifted towards the TiO2-x region with applied bias to gradually increase the thickness of TiO2 region. A comparison of the electrical characteristics of the device when the TiO2 region is extended towards TiO2-x region is also presented. The basis of memristive behavior, the nonlinear hysteresis curve of memristor, has been obtained based upon the simulation results.
    Keywords: memristors; platinum; titanium compounds; I-V curves; Pt-TiO2-x-TiO2-Pt; electrical characteristics; electrical circuit element; first principle DFT simulations; flash storage technology; memristive systems; memristor; nonlinear hysteresis curve; transistors; DRAM; hysteresis; ATK; Application
    Area: interfaces
    BibTeX: 
    @inproceedings{Chakraverty2012,
  author = {Chakraverty, M. and Kittur, H.M.},
  title = {Evidence of hysteresis from first principle DFT simulations of I-V curves in Pt/TiO(2-x) - TiO2/Pt memristive systems},
  booktitle = {Devices, Circuits and Systems (ICDCS), 2012 International Conference on},
  year = {2012},
  pages = {379--383},
  doi = {http://dx.doi.org/10.1109/ICDCSyst.2012.6188749}
}
    Bagavathi Chandrasekara & K A Narayanankutty Gallium Nitride Nanotube and its Application as Transistors

    [Abstract] [BibTeX]

    		 2012 International Journal of Computer Applications
    Vol. 47, 0975-888     		 DOI URL 
    Abstract: In search of opto-electronic nano materials, we often come across Gallium Nitride nanotubes (GaN-NT) with excellent electrical and optical characteristics. Gallium Nitride nanotubes are predominantly semiconducting and have been less explored in its application as a transistor channel through Density Functional Theory (DFT). Comparing Gallium Nitride nanotubes with Boron Nitride nanotubes (BN-NT) and Carbon nanotubes (CNT), we have obtained distinguishing features of Gallium Nitride nanotubes. In this work, Transistor simulation with Gallium Nitride nanotubes has been reported with the nanotube as channel. Properties of various configurations of nanotubes are compared among Carbon, Boron Nitride and Gallium Nitride nanotubes.
    Keywords: ATK; Application; Gallium Nitride nanotubes; GaN nanotube transistor; Density Functional Theory (DFT); bond rotation; Boron Nitride nanotubes
    Area: nanotubes
    BibTeX: 
    @article{Chandrasekara2012,
  author = {Bagavathi Chandrasekara and K A Narayanankutty},
  title = {Gallium Nitride Nanotube and its Application as Transistors},
  journal = {International Journal of Computer Applications},
  year = {2012},
  volume = {47},
  pages = {0975-888},
  url = {http://www.ijcaonline.org/archives/volume47/number14/7259-0347},
  doi = {http://dx.doi.org/10.5120/7259-0347}
}
    Satyendra Singh Chauhan, Pankaj Srivastava & Ashwani Kumar Shrivastava Band Gap Engineering in Zigzag Graphene NanoribbonsAn Ab Initio Approach

    [Abstract] [BibTeX]

    		 2012 Journal of Computational and Theoretical Nanoscience
    Vol. 9(8), 1084-1089     		 DOI  
    Abstract: We present first principles study based on spin polarized density functional theory for electronic properties of armchair graphene nanoribbons (AGNRs) and Bloch state study in zigzag graphene nanoribbons (ZGNRs) passivated with hydrogen atoms. We have investigated the spin-dependent band structure of zigzag graphene nanoribbons. It is observed that these zigzag ribbons are metallic without spin consideration while band gap opens up when spin included. We have also plotted conduction and valence band Bloch states for various k-points and observed that the two spincomponents are localized on opposite sides of the ribbon.
    Keywords: armchair; zigzag; band gap; electronic properties; stability; Bloch states; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Chauhan2012,
  author = {Chauhan, Satyendra Singh and Srivastava, Pankaj and Shrivastava, Ashwani Kumar},
  title = {Band Gap Engineering in Zigzag Graphene NanoribbonsAn Ab Initio Approach},
  journal = {Journal of Computational and Theoretical Nanoscience},
  year = {2012},
  volume = {9},
  number = {8},
  pages = {1084--1089},
  doi = {http://dx.doi.org/10.1166/jctn.2012.2147}
}
    R. Chowdhury Conductance of graphene nanoribbons under mechanical deformation

    [Abstract] [BibTeX]

    		 2012 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 44(7-8), 1256-1259     		 DOI URL 
    Abstract: Graphene is a material system of increasing technological importance with excellent mechanical and electrical properties. Depending on the edge configuration, graphene may be electrically conducting, semiconducting, or insulating, so deformation is believed to have strong effects on electrical properties. In this letter, ab initio approach is used to demonstrate the effect of torsional and strain induced deformation on the electrical conductance characteristics. These nanostructures are described using a single-band tight-binding Hamiltonian. Important observations on the connection between mechanical and electrical behavior are made based on the transport calculations. In particular, the conductance behavior shows interesting features on deformed graphene.
    Keywords: ATK; Application; graphene nanoribbon; mechanical properties;
    Area: graphene
    BibTeX: 
    @article{Chowdhury2012a,
  author = {Chowdhury, R.},
  title = {Conductance of graphene nanoribbons under mechanical deformation},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2012},
  volume = {44},
  number = {7-8},
  pages = {1256--1259},
  url = {http://www.sciencedirect.com/science/article/pii/S1386947712000379},
  doi = {http://dx.doi.org/10.1016/j.physe.2012.01.023}
}
    R. Chowdhury, F. Scarpa & S. Adhikari Molecular-scale bio-sensing using armchair graphene

    [Abstract] [BibTeX]

    		 2012 Journal of Applied Physics
    Vol. 112(1), 014905     		 DOI  
    Abstract: We evaluate the transport properties performance of armchair graphene nanoribbons (AGNRs) with a bio-molecule assembly as potential molecular-scale biosensors (Anthracene). The bio-molecules are assumed to be absorbed at the edge of an AGNR, and to behave as quasi-1D systems. The transport spectrum and density of states (DOS) are calculated using a single-band tight-binding Hamiltonian representation, and a non-equilibrium Greens function formalism. Doping with boron and nitride atoms and its impact on the transport properties has also been evaluated. Significant changes in transmission and increase in DOS by 200% are observed when the Anthracene molecule is interacting with the AGNR. Boron and Nitrogen doping allow to increase current flows at constant voltage by 50% on average. There results suggest potential significant scope on using AGNRs for bio-devices based on either conductance or electroluminescence.
    Keywords: adsorption; biological techniques; biosensors; boron; doping; electrical conductivity; electroluminescence; electronic density of states; fullerene devices; graphene; Green's function methods; molecular biophysics; nanoribbons; nanosensors; nitrogen; organic semiconductors; tight-binding calculations; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Chowdhury2012b,
  author = {R. Chowdhury and F. Scarpa and S. Adhikari},
  title = {Molecular-scale bio-sensing using armchair graphene},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2012},
  volume = {112},
  number = {1},
  pages = {014905},
  doi = {http://dx.doi.org/10.1063/1.4733689}
}
    Bidisa Das & Somobrata Acharya Effect of Point Defects and Impurities on the Electronic Transport of Au Tipped Ultranarrow PbS Nanorods

    [Abstract] [BibTeX]

    		 2012 Journal of Nanoscience and Nanotechnology
    Vol. 12(8), 6258-6264     		 DOI  
    Abstract: Electronic transport through single nanowire/nanorod directly probes the fundamental limits of semiconductor device miniaturization. Point defects or impurity centers form easily during the growth of nanorods/nanowires which may strongly affect the electronic transport efficiencies. Existing models of electronic transport are often unable to determine the role of defects and impurities at the nanoscale because there are significant differences between nanostructures and bulk materials arising from unique geometries and confinement. The effect of defect and impurities on the conductance of a model ultranarrow PbS rod was modeled using density functional theory. It was observed that the introduction of defects and Au impurities modified the orbital energies of PbS nanorods and reduced the conductance compared to the defect-free rod. The conductance for the nanorods with defects and impurities were limited by the number of available conduction channels required for efficient electronic conduction.
    Keywords: ATK; Application; nanowire; colloidal semiconductor nanorods; selective growth; metal tips; rods; conductance
    Area: nanowires
    BibTeX: 
    @article{Das2012,
  author = {Das, Bidisa and Acharya, Somobrata},
  title = {Effect of Point Defects and Impurities on the Electronic Transport of Au Tipped Ultranarrow PbS Nanorods},
  journal = {Journal of Nanoscience and Nanotechnology},
  year = {2012},
  volume = {12},
  number = {8},
  pages = {6258--6264},
  doi = {http://dx.doi.org/10.1166/jnn.2012.6210}
}
    Hiroyuki Fueno, Yoshikazu Kobayashi & Kazuyoshi Tanaka Theoretical study of current-voltage characteristics of carbon nanotube wire functionalized with hydrogen atoms

    [Abstract] [BibTeX]

    		 2012 SCIENCE CHINA Chemistry
    Vol. 55(5), 796-801     		 URL 
    Abstract: A functionalized single-walled carbon nanotube (SWCNT) of a finite length with a ring-like hydrogenation around its surface is designed toward fabrication of a molecular field-effect transistor (FET) device. The molecular wire thus designed is equipped with a quantum dot inside, which is confirmed by theoretical analysis for electronic transport. In particular, the current-voltage (I-V) characteristics under influence of the gate voltage are discussed in detail.
    Keywords: ATK; Application; nanotube; molecular field-effect transistor; FET; device
    Area: nanotubes
    BibTeX: 
    @article{Fueno2012,
  author = {Fueno, Hiroyuki and Kobayashi, Yoshikazu and Tanaka, Kazuyoshi},
  title = {Theoretical study of current-voltage characteristics of carbon nanotube wire functionalized with hydrogen atoms},
  journal = {SCIENCE CHINA Chemistry},
  publisher = {Science China Press, co-published with Springer},
  year = {2012},
  volume = {55},
  number = {5},
  pages = {796--801},
  url = {http://dx.doi.org/10.1007/s11426-012-4499-8}
}
    Tingkun Gu, Tomofumi Tada & Satoshi Watanabe Conductive Path Formation in the Ta2O5 Atomic Switch: First-Principles Analyses

    [Abstract] [BibTeX]

    		 2010 ACS Nano
    Vol. 4(11)ACS Nano, 6477-6482     		 DOI  
    Abstract: The conductive path formed by the interstitial Cu or oxygen vacancies in the Ta2O5 atomic switch were investigated in detail by first-principles methods. The calculated results indicated that the defect state induced by the interstitial Cu is located just at the Fermi level of the Cu and Pt electrodes in the Cu/Ta2O5/Pt heterostructure and that a conduction channel is formed in the Ta2O5 film via the interstitial Cu. On the other hand, oxygen vacancies in Ta2O5 do not form such a conduction channel because of the lower energy positions of their defect states. The above results suggest that the conductive path could be formed by interstitial Cu in the Ta2O5 atomic switch, whereas the oxygen vacancies do not contribute to the formation of the conductive path.
    Keywords: ab initio calculations; copper; density functional theory; energy gap; Green's function methods; metal-insulator boundaries; platinum; Schottky barrier height (SBH); tantalum compounds; ATK; Application; interfaces; resistive switch;
    Area: interfaces
    BibTeX: 
    @article{Gu2010,
  author = {Gu, Tingkun and Tada, Tomofumi and Watanabe, Satoshi},
  title = {Conductive Path Formation in the Ta2O5 Atomic Switch: First-Principles Analyses},
  booktitle = {ACS Nano},
  journal = {ACS Nano},
  publisher = {American Chemical Society},
  year = {2010},
  volume = {4},
  number = {11},
  pages = {6477--6482},
  doi = {http://dx.doi.org/10.1021/nn101410s}
}
    C. Guo, Z.H. Zhang, G. Kwong, J.B. Pan, X.Q. Deng & J.J. Zhang Enormously Enhanced Rectifying Performances by Modification of Carbon Chains for D-sigma-A Molecular Devices

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(23)The Journal of Physical Chemistry C, 12900-12905     		 DOI  
    Abstract: By using the carbon chain as the end group attached to either the left or right side or both sides of the D-sigma-A molecule, we investigate theoretically its rectifying performance. Interestingly, the currently reported highest rectification ratio, 408, with the density functional calculations for a unimolecule device with metal electrodes can be obtained when both carbon chains are symmetrically attached to both sides of the D-sigma-A molecule. Our finding implies that to greatly promote rectifying characteristics of the D-sigma-A molecule the suitable end-group engineering might be a key issue, and increasing geometrical asymmetries of a molecule may not be the only effective way.
    Keywords: ATK; Application; molecular electronics; rectification
    Area: molecular electronics
    BibTeX: 
    @article{Guo2012,
  author = {Guo, C. and Zhang, Z. H. and Kwong, G. and Pan, J. B. and Deng, X. Q. and Zhang, J. J.},
  title = {Enormously Enhanced Rectifying Performances by Modification of Carbon Chains for D-sigma-A Molecular Devices},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {23},
  pages = {12900--12905},
  doi = {http://dx.doi.org/10.1021/jp302254f}
}
    Jing Huang, Weiyi Wang, Shangfeng Yang, Haibin Su, Qunxiang Li & Jinlong Yang A theoretical study of spin-polarized transport properties of planar four-coordinate Fe complexes

    [Abstract] [BibTeX]

    		 2012 Chemical Physics Letters
    Vol. 539-540(0), 102-106     		 DOI  
    Abstract: We present a first-principles study of the spin-polarized transport properties of three planar four-coordinate Fe complexes with different noninnocent ligands sandwiched between two armchair (5,5) single-walled carbon nanotube (SWCNT) electrodes. Theoretical results clearly reveal that the current of the spin-up electrons through three examined molecular junctions is significant larger than that of the spin-down electrons. The low bias conductance is determined by the tail of transmission peak coming from the perturbed lowest unoccupied molecular orbital of the spin-up electrons. The high spin-filter efficiencies (up to 99.0%) are predicted for three planar four-coordinate Fe complexes coupled to SWCNTs.
    Keywords: ATK; Application; molecular electronics; nanotube; spin
    Area: molecular electronics; nanotubes; spin
    BibTeX: 
    @article{Huang2012a,
  author = {Huang, Jing and Wang, Weiyi and Yang, Shangfeng and Su, Haibin and Li, Qunxiang and Yang, Jinlong},
  title = {A theoretical study of spin-polarized transport properties of planar four-coordinate Fe complexes},
  journal = {Chemical Physics Letters},
  year = {2012},
  volume = {539-540},
  number = {0},
  pages = {102--106},
  doi = {http://dx.doi.org/10.1016/j.cplett.2012.05.002}
}
    Jing Huang, Weiyi Wang, Shangfeng Yang, Qunxiang Li & Jinlong Yang Efficient spin filter based on FeN_4 complexes between carbon nanotube electrodes

    [Abstract] [BibTeX]

    		 2012 Nanotechnology
    Vol. 23(25), 255202     		 DOI URL 
    Abstract: We present a theoretical study to explore the spin transport properties of FeN 4 complexes sandwiched between two armchair (5, 5) carbon nanotube (CNT) electrodes. The ab-initio modeling is performed by combining the spin-dependent density functional theory with nonequilibrium Green's function formalism. The calculated results clearly demonstrate that the transport properties of FeN 4 complexes are sensitive to the contact configuration. Near the Fermi level the conductance through three examined junctions is mainly governed by the spin-up electrons. The FeN 4 complex coupled to CNT electrodes with the pi-type contact conjugation can act as a nearly perfect spin filter, and its spin filter efficiency is up to 98.0%. Our theoretical results demonstrate that FeN 4 complexes are promising for future molecular spintronics devices.
    Keywords: spin; nanotube; ATK; Application; spin filtering; spintronics
    Area: nanotubes; spin
    BibTeX: 
    @article{Huang2012b,
  author = {Jing Huang and Weiyi Wang and Shangfeng Yang and Qunxiang Li and Jinlong Yang},
  title = {Efficient spin filter based on FeN_4 complexes between carbon nanotube electrodes},
  journal = {Nanotechnology},
  year = {2012},
  volume = {23},
  number = {25},
  pages = {255202},
  url = {http://stacks.iop.org/0957-4484/23/i=25/a=255202},
  doi = {http://dx.doi.org/10.1088/0957-4484/23/25/255202}
}
    Neeraj K. Jaiswal & Pankaj Srivastava First principles calculations of cobalt doped zigzag graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Solid State Communications
    Vol. 152(15)Exploring Graphene, Recent Research Advances, 1489-1492     		 DOI URL 
    Abstract: We have investigated the stability and electronic properties of Co-doped zigzag graphene nanoribbons (ZGNR) by employing first principles calculations based on density functional theory. The results show that Co impurities settled in antiferromagnetic ground state which is ~2 meV favourable than ferromagnetic state. The formation energy indicates spontaneous formation of one-edge and centre doped structures, however, one-edge doping is found to be the most energetically favourable configuration. A charge transfer takes place from C to Co atoms which shows the formation of chemical bonding between C and Co. Binding energy also confirms the strong bonding of dopant Co impurity with C. The calculations show that band structures of all the ZGNR is substantially modified due to Co-C charge transfer and the characteristic edge states of ZGNR are completely lost. Co-doping induces site independent enhanced metallicity irrespective of the ribbon widths. The broken degeneracy of electronic states in one-edge and centre doped ZGNR is important for spintronic applications.
    Keywords: graphene nanoribbon; doping; electronic band structure; ATK; Application; spin
    Area: graphene; spin
    BibTeX: 
    @article{Jaiswal2012a,
  author = {Jaiswal, Neeraj K. and Srivastava, Pankaj},
  title = {First principles calculations of cobalt doped zigzag graphene nanoribbons},
  booktitle = {Exploring Graphene, Recent Research Advances},
  journal = {Solid State Communications},
  year = {2012},
  volume = {152},
  number = {15},
  pages = {1489--1492},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109812002530},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.04.047}
}
    V K Lamba & D Engles Modifying the Electronic Properties of Nano-Structures Using Strain

    [Abstract] [BibTeX]

    		 2012 Journal of Physics: Conference Series
    Vol. 377(1), 012069     		 DOI  
    Abstract: We used density-functional theory based Non equilibrium green function simulations to study the effects of strain and quantum confinement on the electronic properties of Germanium & Silicon NWs along the [110] direction, such as the energy gap and the effective masses of the electron and hole. The diameters of the NWs being studied in a range of 3-20 Å. On basis of our calculation we conclude that the Ge [110] NWs possess a direct band gap, while Si [110] NWs possess indirect band gap at nanoscale. The band gap is almost a linear function of strain when the diameter of Ge NWs D < 10 Å while shows parabolic behaviour for, D > 15 Å; & for Si it is linear in behaviour. On doping silicon wire we found that the bandgap shows parabolic behaviour for change in strain. We also concluded that the band gap and the effective masses of charge carries (i.e. electron & hole) changes by applying the strain to the NWs. Our results suggested that strain can be used to tune the ba nd structures of NWs, which may help in de sign of future nanoelectronic devices.
    Keywords: ATK; Application; strain; nanowire;
    Area: nanowires
    BibTeX: 
    @article{Lamba2012,
  author = {V K Lamba and D Engles},
  title = {Modifying the Electronic Properties of Nano-Structures Using Strain},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {377},
  number = {1},
  pages = {012069},
  doi = {http://dx.doi.org/10.1088/1742-6596/377/1/012069}
}
    Hong Li, Nabil Al-Aqtash, Lu Wang, Rui Qin, Qihang Liu, Jiaxin Zheng, Wai-Ning Mei, R.F. Sabirianov, Zhengxiang Gao & Jing Lu Electromechanical switch in metallic graphene nanoribbons via twisting

    [Abstract] [BibTeX]

    		 2012 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 44(10), 2021-2026     		 DOI  
    Abstract: We imposed screwing operation to a metallic ferromagnetic zigzag-edged graphene nanoribbon (ZGNR) with a narrow width and a finite length, and the polarized charge transport is investigated by using Nonequilibrium Green's function in combination with density functional theory. The current are nearly completely suppressed when the ZGNRs are overturned. Inspiringly, this metal-to-semiconductor transition tuned by screwing operation is reversible. Hence our investigation brings forward a novel electromechanical switch, and such a switch is equivalent to a spin valve without resort to an external magnetic field.
    Keywords: ATK; Application; mechanical; electromechanical; graphene nanoribbon;
    Area: graphene
    BibTeX: 
    @article{Li2012g,
  author = {Li, Hong and Al-Aqtash, Nabil and Wang, Lu and Qin, Rui and Liu, Qihang and Zheng, Jiaxin and Mei, Wai-Ning and Sabirianov, R.F. and Gao, Zhengxiang and Lu, Jing},
  title = {Electromechanical switch in metallic graphene nanoribbons via twisting},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2012},
  volume = {44},
  number = {10},
  pages = {2021--2026},
  doi = {http://dx.doi.org/10.1016/j.physe.2012.06.004}
}
    Enling Li, Liping Hou, Zhen Cui, Danna Zhao, Mancang Liu & Xuewen Wang Electronic structures and transport properties of single crystalline GaN nanotubes

    [Abstract] [BibTeX]

    		 2012 Nano
    Vol. 07(03)Nano, 1250014     		 DOI  
    Abstract: The electronic structures and transport properties of single crystalline GaN nanotubes with 0.92 nm inner diameter and different wall thicknesses of 0.08 nm, 0.26 nm and 0.54 nm are studied based on the generalized gradient approximation (GGA) of density functional theory (DFT) and the nonequilibrium green's function (NEGF). The research shows that (1) the three single crystalline GaN nanotubes have direct band gaps, decreasing with the increase of wall thickness; (2) the electronic density of state and electronic transmission spectra of two-probe system have their own pulse-type sharp peaks with almost the same location of electron energy; (3) under different bias-voltages, two-probe systems of the single crystalline GaN nanotubes have the I-V properties which reveal that the single-wall GaN nanotube and the single-layer GaN nanotube are semiconducting and the double-layer GaN nanotube appears nearly metallic.
    Keywords: ATK; Application; GaN nanotubes; electronic transport; density functional theory (DFT);
    Area: nanotubes
    BibTeX: 
    @article{Li2012h,
  author = {Li, Enling and Hou, Liping and Cui, Zhen and Zhao, Danna and Liu, Mancang and Wang, Xuewen},
  title = {Electronic structures and transport properties of single crystalline GaN nanotubes},
  booktitle = {Nano},
  journal = {Nano},
  publisher = {World Scientific Publishing Co.},
  year = {2012},
  volume = {07},
  number = {03},
  pages = {1250014},
  doi = {http://dx.doi.org/10.1142/S1793292012500142}
}
    J. Li, Z.H. Zhang, J.J. Zhang & X.Q. Deng Rectifying regularity for a combined nanostructure of two trigonal graphenes with different edge modifications

    [Abstract] [BibTeX]

    		 2012 Organic Electronics
    Vol. 13(11), 2257-2263     		 DOI  
    Abstract: The metal- or nonmetal-terminated left zigzag-edge trigonal graphene (M-LTGN or NM-LTGN) is linked to the H-terminated right zigzag-edge trigonal graphene (H-RTGN) through their vertex atoms wholly attached onto Au electrodes to construct nanojunctions. Calculated results show that their rectifying behaviors have very interesting regularities: the rectifying directions for M-LTGN/H-RTGN nanojunction and NM-LTGN/H-RTGN nanojunction are opposite, and the stronger the nonmetallic (metallic) behavior for atom terminated at edge of the LTGN, the larger its rectification ratio for a forward (reverse) rectification. The intrinsic mechanism for these features can be attributed to a Schottky barrier on interface when they are combined due to the charge shifting doping between them. Findings unveiled here are of importance for achieving a profound understanding and developing nanoelectronic devices on the TGN functionalized by edge modification.
    Keywords: zigzag-edge trigonal graphene; edge modification; rectifying behavior; Schottky barrier; density-functional theory; ATK; Application
    Area: molecular electronics; graphene
    BibTeX: 
    @article{Li2012i,
  author = {Li, J. and Zhang, Z.H. and Zhang, J.J. and Deng, X.Q.},
  title = {Rectifying regularity for a combined nanostructure of two trigonal graphenes with different edge modifications},
  journal = {Organic Electronics},
  year = {2012},
  volume = {13},
  number = {11},
  pages = {2257--2263},
  doi = {http://dx.doi.org/10.1016/j.orgel.2012.07.010}
}
    E.L. Li, Z. Cui, M.C. Liu & X.W. Wang First-Principles Study on Transport Properties of Saturated Single Crystalline GaN Nanotubes

    [Abstract] [BibTeX]

    		 2012 Integrated Ferroelectrics
    Vol. 137, 134-142     		 DOI  
    Abstract: Electronic structures and transport properties of the saturated single crystalline GaN nanotubes with 0.92 nm inner diameter and different wall thickness have been investigated by using first-principles and non-equilibrium Green's function (NEGF). The result shows, the energy gap of the saturated single crystalline nanotubes changed from 0.2933 to 2.8442 eV. The saturated single crystalline GaN nanotubes have the direct band gap and the band gap decreases with the increase of wall thickness of nanotubes. The electronic density of state and the electronic transmission spectra of two-probe system have pulse-type sharp peak, the change of electronic density of state is in accord with electronic transmission rate. I-V characteristics of two-probe systems reflect that the saturated single-wall GaN nanotube and the saturated single-layer GaN nanotube are semiconducting properties, and the saturated double-layer GaN nanotube appears metallic behavior.
    Keywords: nanotubes; ATK; Application; GaN;
    Area: nanowires
    BibTeX: 
    @article{Li2012j,
  author = {Li, E. L. and Cui, Z. and Liu, M. C. and Wang, X. W.},
  title = {First-Principles Study on Transport Properties of Saturated Single Crystalline GaN Nanotubes},
  journal = {Integrated Ferroelectrics},
  publisher = {Taylor & Francis Ltd},
  year = {2012},
  volume = {137},
  pages = {134--142},
  doi = {http://dx.doi.org/10.1080/10584587.2012.687319}
}
    An Li-Ping, Liu Chun-Mei & Liu Nian-Hua Negative Differential Resistance in Atomic Carbon Chain-Graphene Junctions

    [Abstract] [BibTeX]

    		 2012 Communications in Theoretical Physics
    Vol. 57(6), 1087     		 DOI  
    Abstract: We investigate the electronic transport properties of atomic carbon chain-graphene junctions by using the density-functional theory combining with the non-equilibrium Green's functions. The results show that the transport properties are sensitively dependent on the contact geometry of carbon chain. From the calculated I-V curve we find negative differential resistance (NDR) in the two types of junctions. The NDR can be considered as a result of molecular orbitals moving related to the bias window.
    Keywords: ATK; Application; graphene; negative differential resistance; NDR
    Area: graphene
    BibTeX: 
    @article{Li-Ping2012,
  author = {An Li-Ping and Liu Chun-Mei and Liu Nian-Hua},
  title = {Negative Differential Resistance in Atomic Carbon Chain-Graphene Junctions},
  journal = {Communications in Theoretical Physics},
  year = {2012},
  volume = {57},
  number = {6},
  pages = {1087},
  doi = {http://dx.doi.org/10.1088/0253-6102/57/6/25}
}
    Xin Luo, Yue Zheng & Biao Wang First-principles calculations of size-dependent giant electroresistance effect in nanoscale asymmetric ferroelectric tunnel junctions

    [Abstract] [BibTeX]

    		 2012 Journal of Applied Physics
    Vol. 111(7), 074102     		 DOI URL 
    Abstract: Based on the first principle calculations, we predicted the electronic structures and ferroelectric instability of the asymmetric ferroelectric tunneling junction with the ferroelectric barrier thickness changing, and found two undiscovered and important behaviors, i.e., absence of the critical thickness for the positive polarization state and the larger critical thickness for the negative polarization state. Using nonequilibrium Green function's approach, the corresponding two-probe systems and their electronic transport properties at different ferroelectric barrier thickness have been constructed. It is found that reorienting the polarization direction in the ferroelectric barrier can dramatically change the internal electric field and macroscopic potential barrier, resulting in several orders of magnitude change in tunneling electroresistance ratio. Results also found that the tunneling electroresistance can be distinctly controlled by adjusting thickness of the ferroelectric barrier, which behavior is defined as the size-dependent giant electroresistance effect. Our results enable architectures of large density and high sensitivity in the next generation of ferroelectric random access memories with nondestructive resistive readout.
    Keywords: ab initio calculations; band structure; barium compounds; ferroelectric devices; ferroelectric materials; ferroelectric storage; ferroelectricity; Green's function methods; nanotechnology; platinum; random-access storage; strontium compounds; ATK; Application
    Area: interfaces
    BibTeX: 
    @article{Luo2012,
  author = {Xin Luo and Yue Zheng and Biao Wang},
  title = {First-principles calculations of size-dependent giant electroresistance effect in nanoscale asymmetric ferroelectric tunnel junctions},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2012},
  volume = {111},
  number = {7},
  pages = {074102},
  url = {http://link.aip.org/link/?JAP/111/074102/1},
  doi = {http://dx.doi.org/10.1063/1.3698503}
}
    JiaSai Ma, HaiMing Dong, DongMei Li & DeSheng Liu Negative differential resistance behaviors in OPE derivatives combined C60 molecular junctions modulated with side groups

    [Abstract] [BibTeX]

    		 2012 SCIENCE CHINA Physics, Mechanics & Astronomy
    Vol. 55, 1412-1416     		 DOI  
    Abstract: By applying non-equilibrium Green's functions (NEGF) in combination with the density functional theory (DFT), we investigate the electronic transport properties of molecular junctions constructed by OPE derivatives with different side groups combined C 60 molecules. The results show that the side groups play an important role in the properties of electron transport. Negative differential resistance (NDR) is observed in such devices. Especially for the molecule with electron-donating group (-OCH3), two NDR appear at different bias voltage regions. And the mechanism is proposed for the NDR behavior, owing to the shift of the molecular orbitals caused by the change in molecule charge.
    Keywords: self-assembled monolayers; device; negative differential resistance; NDR; electronic transport; non-equilibrium Green's function; side groups; molecular electronics; fullerenes; C60; OPE; ATK; Application
    Area: molecular electronics; fullerenes
    BibTeX: 
    @article{Ma2012,
  author = {Ma, JiaSai and Dong, HaiMing and Li, DongMei and Liu, DeSheng},
  title = {Negative differential resistance behaviors in OPE derivatives combined C60 molecular junctions modulated with side groups},
  journal = {SCIENCE CHINA Physics, Mechanics & Astronomy},
  publisher = {Science China Press, co-published with Springer},
  year = {2012},
  volume = {55},
  pages = {1412-1416},
  note = {10.1007/s11433-012-4768-8},
  doi = {http://dx.doi.org/10.1007/s11433-012-4768-8}
}
    Duan Man-Yi, Shi Guo-Sheng, Wang Chun-Lei, Zhou Li-Ping, Chen Xiang-Rong & Fang Hai-Ping A Theoretical Study of a Single-Walled ZnO Nanotube as a Sensor for H2O Molecules

    [Abstract] [BibTeX]

    		 2012 Communications in Theoretical Physics
    Vol. 58(2), 275     		 DOI URL 
    Abstract: We have studied the property of single-walled ZnO nanotubes with adsorbed water molecules, and theoretically designed a new sensor for detecting water molecules using single-walled ZnO nanotubes using a combination of density functional theory and the non-equilibrium Green's function method. Details of the geometric structures and adsorption energies of the H 2 O molecules on the ZnO nanotube surface have been investigated. Our computational results demonstrate that the formation of hydrogen bonding between the H 2 O molecules and the ZnO nanotube, and adsorption energies of the H 2 O molecules on the ZnO nanotube are larger than the adsorption energies of other gas molecules present in the atmospheric environment. Moreover, the current-voltage curves of the ZnO nanotube with and without H 2 O molecules adsorbed on its surface are calculated, the results of which showed that the H 2 O molecules form stable adsorption configurations that could lead to the decrease in current. These results suggest that the single-walled ZnO nanotubes are able to detect and monitor the presence of H 2 O molecules by applying bias voltages.
    Keywords: ATK; Application; ZnO nanotube; sensor; electronic-properties; magnetic-properties; adsorption; 1st-principles
    Area: nanotubes
    BibTeX: 
    @article{Man-Yi2012,
  author = {Duan Man-Yi and Shi Guo-Sheng and Wang Chun-Lei and Zhou Li-Ping and Chen Xiang-Rong and Fang Hai-Ping},
  title = {A Theoretical Study of a Single-Walled ZnO Nanotube as a Sensor for H2O Molecules},
  journal = {Communications in Theoretical Physics},
  year = {2012},
  volume = {58},
  number = {2},
  pages = {275},
  url = {http://stacks.iop.org/0253-6102/58/i=2/a=18},
  doi = {http://dx.doi.org/10.1088/0253-6102/58/2/18}
}
    Argo Nurbawono, Aihua Zhang, Yongqing Cai, Yihong Wu, Yuan Ping Feng & Chun Zhang Nanowelding of carbon nanotube-metal contacts: An effective way to control the Schottky barrier and performance of carbon nanotube based field effect transistors

    [Abstract] [BibTeX]

    		 2012 The Journal of Chemical Physics
    Vol. 136(17), 174704     		 DOI  
    Abstract: Schottky barriers formed at carbon nanotube (CNT)-metal contacts have been well known to be crucial for the performance of CNT based field effect transistors (FETs). Through first principles calculations we show that a nanowelding process can drastically reduce the Schottky barriers at CNT-metal interfaces, resulting in significantly improved conductivity of CNT-based FETs. The proposed nanowelding can be realized by either laser local heating or a heating process via a controllable pulse current. Results presented in this paper may have great implications in future design and applications of CNT-based electronics.
    Keywords: carbon nanotubes; field effect transistors; nanocontacts; nanofabrication; Schottky barriers; ATK; Application
    Area: nanotubes; interfaces
    BibTeX: 
    @article{Nurbawono2012,
  author = {Argo Nurbawono and Aihua Zhang and Yongqing Cai and Yihong Wu and Yuan Ping Feng and Chun Zhang},
  title = {Nanowelding of carbon nanotube-metal contacts: An effective way to control the Schottky barrier and performance of carbon nanotube based field effect transistors},
  journal = {The Journal of Chemical Physics},
  publisher = {AIP},
  year = {2012},
  volume = {136},
  number = {17},
  pages = {174704},
  doi = {http://dx.doi.org/10.1063/1.4711082}
}
    Anurag Srivastava, Arpit Jain, Rajnish Kurchania & Neha Tyagi Width Dependent Electronic Properties of Graphene Nanoribbons: An Ab-Initio Study

    [Abstract] [BibTeX]

    		 2012 Journal of Computational and Theoretical Nanoscience
    Vol. 9(7), 1008-1013     		 DOI  
    Abstract: We have analyzed the electronic properties of armchair and zigzag shaped graphene nanoribbons (GNRs) using density functional theory based ab-initio approach. The present computation employs the Perdew Zunger (PZ) type parameterized local density approximation (LDA) and revised Perdew Burke Ernzerhof (RPBE) type generalized gradient approximation (GGA) as exchange correlation functional. The calculated electronic band gap and density of states shows a close match with its other theoretical counterparts. In another observation, we have found a non linear variation of GNRs energy bandgap as a function of width.
    Keywords: graphene nanoribbons; dft; electronic properties; energy band gap; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Srivastava2012,
  author = {Srivastava, Anurag and Jain, Arpit and Kurchania, Rajnish and Tyagi, Neha},
  title = {Width Dependent Electronic Properties of Graphene Nanoribbons: An Ab-Initio Study},
  journal = {Journal of Computational and Theoretical Nanoscience},
  year = {2012},
  volume = {9},
  number = {7},
  pages = {1008--1013},
  doi = {http://dx.doi.org/10.1166/jctn.2012.2133}
}
    Anurag Srivastava & Neha Tyagi Pressure induced zincblende to rocksalt phase transition in AlN nanocrystal

    [Abstract] [BibTeX]

    		 2012 Journal of Physics: Conference Series
    Vol. 377(1), 012066     		 DOI  
    Abstract: Structural phase transition in Aluminium nitride (AlN) nanocrystal has been studied within the framework of density-functional theory, using both the local-density as well as generalized gradient approximation as exchange correlation functionals. The study observes that under the application of pressure AlN nanocrystal transforms from its original zincblende (B3) type phase to hypothetical rocksalt (B1) type phase within the pressure range of 46 GPa to 56 GPa, which is comparatively larger than its bulk counterpart. The lattice parameter, bulk modulus and pressure derivatives of AlN nanocrystal in its original B3 type phase as well as hypothetical B1 type phase have also been computed as ground state properties. The mechanical strength of the AlN nanocrystal has been analysed in terms of volume collapse at transition pressure and bulk modulus.
    Keywords: ATK; Application; nanocrystal; phase transition;
    Area: semi
    BibTeX: 
    @article{Srivastava2012a,
  author = {Anurag Srivastava and Neha Tyagi},
  title = {Pressure induced zincblende to rocksalt phase transition in AlN nanocrystal},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {377},
  number = {1},
  pages = {012066},
  doi = {http://dx.doi.org/10.1088/1742-6596/377/1/012066}
}
    Anurag Srivastava & Neha Tyagi Pressure-induced phase transition in Ga1-xInxAs: ab initio study

    [Abstract] [BibTeX]

    		 2012 High Pressure Research
    Vol. 32(2)High Pressure Research, 299-308     		 DOI  
    Abstract: The high pressure phase transitions in Ga 1-x In x As (x=0.25, 0.5 and 0.75) alloys have been investigated using the ab initio density functional theory approach. The total energies and ground state properties have been analyzed using both the local density as well as generalized gradient approximations as exchange-correlation functionals. The study computes the structural phase transition in Ga 1-x In x As from its most stable zinc-blende- (B3) type phase to hypothetical rocksalt- (B1) type phase in the pressure range of 3-14 GPa. The observed transition pressures for the host binary compounds are in close agreement with their experimental/theoretical counterparts. The effect of introduction of indium in GaAs has also been analyzed on the lattice parameter, bulk modulus and transition pressure.
    Keywords: ab initio; phase transition; high pressure; alloys; III-V zincblende semiconductors; absorption fine-structure; random solid-solutions; electronic-structure; vibrational properties; molecular-dynamics; ATK; Application
    Area: semi
    BibTeX: 
    @article{Srivastava2012b,
  author = {Srivastava, Anurag and Tyagi, Neha},
  title = {Pressure-induced phase transition in Ga1-xInxAs: ab initio study},
  booktitle = {High Pressure Research},
  journal = {High Pressure Research},
  publisher = {Taylor & Francis},
  year = {2012},
  volume = {32},
  number = {2},
  pages = {299--308},
  doi = {http://dx.doi.org/10.1080/08957959.2012.686613}
}
    G.P. Tang, J.C. Zhou, Z.H. Zhang, X.Q. Deng & Z.Q. Fan Altering regularities of electronic transport properties in twisted graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 101(2), 023104     		 DOI  
    Abstract: Based on density-function theory combined with nonequilibrium Green's function method, the electronic transport properties of twisted armchair- and zigzag-edge graphene nanoribbons (AGNRs and ZGNRs) are investigated. Results show that electronic transport properties are sensitive to twisting deformations for semiconductor-type AGNRs, but are robust against twisting deformations for quasi-metallic AGNRs and ZGNRs. The electronic conduction becomes weaker gradually for moderate-gap semiconductor-type AGNRs, but gets stronger for wide-gap semiconductor-type AGNRs when the twisted angle increases to 120°. While for quasi-metallic AGNRs and ZGNRs, the electronic conduction is strong and obeys Ohm's law of resistance strictly. Mechanisms for such results are suggested.
    Keywords: density functional theory; electrical conductivity; graphene; Green's function methods; nanoribbons; wide band gap semiconductors; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Tang2012,
  author = {G. P. Tang and J. C. Zhou and Z. H. Zhang and X. Q. Deng and Z. Q. Fan},
  title = {Altering regularities of electronic transport properties in twisted graphene nanoribbons},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {101},
  number = {2},
  pages = {023104},
  doi = {http://dx.doi.org/10.1063/1.4733618}
}
    Yuta Tsuji, Aleksandar Staykov & Kazunari Yoshizawa Orbital Determining Spintronic Properties of a pi-Conjugated System

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(30)The Journal of Physical Chemistry C, 16325-16332     		 DOI  
    Abstract: Spintronic properties of cyclobutadiene (CBD) systems are investigated based on a qualitative frontier orbital analysis. CBD undergoes a Jahn-Teller distortion from the square triplet state to the rectangular singlet state. According to the qualitative Hückel molecular orbital analysis, the electron transport through the square triplet state is symmetry allowed, whereas that through the rectangular singlet state is symmetry forbidden. The magnetic triplet state is a possible coexisting system of conductivity and magnetism. Sophisticated first-principles quantum chemical calculations are performed by using a realistic molecular junction model. Obtained results are in good agreement with the prediction based on the qualitative orbital analysis. Interesting spin filtering properties are found in the square-shaped CBD system. The high- and low-spin states of the square-shaped CBD system produce the spin-up and spin-down polarized conductance, respectively. The qualitative orbital analysis is useful as a guiding principle for designing molecular spintronics.
    Keywords: ATK; Application; molecular electronics; spin; spintronics; metal atom chains; electron-transport; cyclobutadiene dianion; magnetic-field; molecular wire; conductance; density; views; ring; hydrocarbons
    Area: molecular electronics; spin
    BibTeX: 
    @article{Tsuji2012,
  author = {Tsuji, Yuta and Staykov, Aleksandar and Yoshizawa, Kazunari},
  title = {Orbital Determining Spintronic Properties of a pi-Conjugated System},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {30},
  pages = {16325--16332},
  doi = {http://dx.doi.org/10.1021/jp305448q}
}
    Cai-Juan Xia, De-Sheng Liu & Han-Chen Liu Phenylazoimidazole as a possible optical molecular switch: An ab initio study

    [Abstract] [BibTeX]

    		 2012 Optik - International Journal for Light and Electron Optics
    Vol. 123(14), 1307-1310     		 DOI URL 
    Abstract: By applying nonequilibrium Green's function formalism combined first-principles density functional theory, we investigate the electronic transport properties of the phenylazoimidazole optical molecular switch. The molecule that comprises the switch can convert between the cis and the trans forms upon photoexcitation. The influence of HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the electronic transport through the molecular device are discussed in detail. Theoretical results show that the current through the trans form is significantly larger than through the cis form, which suggests this system has attractive potential application in future molecular switch technology.
    Keywords: Molecular switch; Nonequilibrium Green's function; Electronic transport; Density functional theory; ATK; Application; optical switch
    Area: molecular electronics
    BibTeX: 
    @article{Xia2012d,
  author = {Xia, Cai-Juan and Liu, De-Sheng and Liu, Han-Chen},
  title = {Phenylazoimidazole as a possible optical molecular switch: An ab initio study},
  journal = {Optik - International Journal for Light and Electron Optics},
  year = {2012},
  volume = {123},
  number = {14},
  pages = {1307--1310},
  url = {http://www.sciencedirect.com/science/article/pii/S0030402611004554},
  doi = {http://dx.doi.org/10.1016/j.ijleo.2011.08.012}
}
    Cai-Juan Xia, Ying-Tang Zhang & De-Sheng Liu Effect of torsion angle on the rectifying performance in the donor-bridge-acceptor single molecular device

    [Abstract] [BibTeX]

    		 2012 J. Theor. Comput. Chem.
    Vol. 11(04)Journal of Theoretical and Computational Chemistry, 735-743     		 DOI  
    Abstract: By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the effect of torsion angle on the rectifying performance in the donor-bridge-acceptor single molecular device. The influence of HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the electronic transport through the molecular device are discussed in detail. The theoretical results show that the torsion angle plays an important role in the rectifying behavior of such devices. By changing the torsion angle, namely changing the magnitude of the intermolecular coupling effect, a different rectifying behavior can be observed in these systems. The results can provide fundamental guidelines for the design of functional molecular devices to a certain extent.
    Keywords: rectifying performance; nonequilibrium Green's function; electronic transport; density functional theory; electromechanical; conductance; switch; electronics; resistance; molecular electronics; ATK; Application;
    Area: molecular electronics
    BibTeX: 
    @article{Xia2012e,
  author = {Xia, Cai-Juan and Zhang, Ying-Tang and Liu, De-Sheng},
  title = {Effect of torsion angle on the rectifying performance in the donor-bridge-acceptor single molecular device},
  booktitle = {Journal of Theoretical and Computational Chemistry},
  journal = {J. Theor. Comput. Chem.},
  publisher = {World Scientific Publishing Co.},
  year = {2012},
  volume = {11},
  number = {04},
  pages = {735--743},
  doi = {http://dx.doi.org/10.1142/S0219633612500496}
}
    Fu-Qiu Ye, Zhi-Qiang Fan, Jun He, Jun Peng & Li-Ming Tang Theoretical investigation on current-voltage characteristics in all-carbon molecular device with different contact geometries

    [Abstract] [BibTeX]

    		 2012 Physica B: Condensed Matter
    Vol. 407(18), 3861-3864     		 DOI  
    Abstract: Applying nonequilibrium Green's functions in combination with the first-principles density-functional theory, we investigate electronic transport properties of an all-carbon molecular device consisting of one phenalenyl molecule and two zigzag graphene nanoribbons. The results show that the electronic transport properties are strongly dependent on the contact geometry and device's currents can drop obviously when the connect sites change from second-nearest sites from the central atom of the molecule (S site) to third-nearest sites from the central atom of the molecule (T site). More importantly, the negative differential resistance behavior is only observed on the negative bias region when the molecule connects the graphene nanoribbons through two T sites.
    Keywords: ATK; Application; nonequilibrium Green's functions; density-functional theory; molecular device; graphene; negative differential resistance behavior
    keywords plus: transport-properties; graphene; electrodes
    Area: graphene
    BibTeX: 
    @article{Ye2012,
  author = {Ye, Fu-Qiu and Fan, Zhi-Qiang and He, Jun and Peng, Jun and Tang, Li-Ming},
  title = {Theoretical investigation on current-voltage characteristics in all-carbon molecular device with different contact geometries},
  journal = {Physica B: Condensed Matter},
  year = {2012},
  volume = {407},
  number = {18},
  pages = {3861--3864},
  doi = {http://dx.doi.org/10.1016/j.physb.2012.06.007}
}
    H L Yu, X F Jiang, Y Zheng & G W Yang An ab initio study of MgO epitaxial layers on a Co 2 MnSi (0 0 1) surface: influence of the interface structure on tunnelling conductance

    [Abstract] [BibTeX]

    		 2012 Journal of Physics D: Applied Physics
    Vol. 45(32), 325002     		 DOI  
    Abstract: The formation of MgO epitaxial layers on a Co 2 MnSi (001) surface was studied using the ab initio electronic structure calculations based on the density functional theory. The free energy calculations showed that the O-rich, O-top and Mg-rich configurations in the CoCo termination case, and the O-rich and O-top configurations in the MnSi termination case were thermodynamically stable. The magnetic and electronic properties of these stable configurations were investigated in detail, and the results indicated that only the Mg-rich configuration with CoCo termination exhibited near half-metallic properties at the interface. The influence of the interfacial structure on the tunnelling conductance of the Co 2 MnSi/MgO/Co 2 MnSi magnetic tunnel junctions (MTJs) was also discussed using the nonequilibrium Green's function method. The attained conductance showed that a large difference of up to 10^4 was observed in the magnitude of parallel conductance, which means that the interface structure plays a crucial role in the electronic transport of the MTJ. These findings are useful in designing MTJs with high performance.
    Keywords: ATK; Application; MTJ; spin; FeMgO; magnetism; tunnel junction
    Area: interfaces; spin; nvm
    BibTeX: 
    @article{Yu2012,
  author = {H L Yu and X F Jiang and Y Zheng and G W Yang},
  title = {An ab initio study of MgO epitaxial layers on a Co 2 MnSi (0 0 1) surface: influence of the interface structure on tunnelling conductance},
  journal = {Journal of Physics D: Applied Physics},
  year = {2012},
  volume = {45},
  number = {32},
  pages = {325002},
  doi = {http://dx.doi.org/10.1088/0022-3727/45/32/325002}
}
    J.J. Zhang, Z.H. Zhang, C. Guo, J. Li & X.Q. Deng Electronic Transport Properties for a Zigzag-Edged Triangular Graphene

    [Abstract] [BibTeX]

    		 2012 Acta Physico-chimica Sinica
    Vol. 28(7), 1701-1706     		 DOI  
    Abstract: Based on the density functional theory and the non-equilibrium Green's function method, the electronic transport properties of zigzag-edged triangular graphene were studied systematically. The results revealed that the current voltage (I-V) characteristics and rectifying effects were closely related to the geometric size and the type of atoms terminated at the edges of triangular graphene. In the case of Hand S-terminated edges, a small triangular graphene had a large current but with a small rectifying ratio. Although the current increased, the rectifying behavior was lowered when H atoms at the edges of the structure were replaced by O atoms. Deeper analysis demonstrated that such a rectification was caused by the asymmetry in the spatial distribution of the frontier orbitals and an asymmetric movement on the molecular-level in triangular graphene under positive and negative biases. It is of great significance that our investigations develop a thorough understanding of the basic physical properties of a triangular graphene.
    Keywords: ATK; Application; nanoribbons; lattices; molecular electronics; graphene; triangular graphene; rectifying effect; electronic transport property; density functional theory; non-equilibrium Green's function method
    Area: graphene; molecular electronics
    BibTeX: 
    @article{Zhang2012c,
  author = {Zhang, J. J. and Zhang, Z. H. and Guo, C. and Li, J. and Deng, X. Q.},
  title = {Electronic Transport Properties for a Zigzag-Edged Triangular Graphene},
  journal = {Acta Physico-chimica Sinica},
  publisher = {Peking Univ Press},
  year = {2012},
  volume = {28},
  number = {7},
  pages = {1701--1706},
  doi = {http://dx.doi.org/10.3866/PKU.WHXB201204172}
}
    Hang Zhang, Jing Zeng & Ke-Qiu Chen Rectifying and negative differential resistance behaviors induced by asymmetric electrode coupling in Pyrene-based molecular device

    [Abstract] [BibTeX]

    		 2012 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 44(7-8), 1631-1635     		 DOI URL 
    Abstract: By applying nonequilibrium Green's functions in combination with density-functional theory, we investigate the effect of asymmetric electrode coupling on electronic transport properties in a Pyrene-based molecular device. The results show that rectifying behaviors can be tuned by changing the coupling degree between Pyrene molecule and electrode. Moreover, negative differential resistance behavior can also be observed in this model. The mechanisms for these interesting phenomena are suggested.
    Keywords: junctions; conductance; transport; rectification; rectifiers; molecular electronics; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Zhang2012d,
  author = {Zhang, Hang and Zeng, Jing and Chen, Ke-Qiu},
  title = {Rectifying and negative differential resistance behaviors induced by asymmetric electrode coupling in Pyrene-based molecular device},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2012},
  volume = {44},
  number = {7-8},
  pages = {1631--1635},
  url = {http://www.sciencedirect.com/science/article/pii/S1386947712001543},
  doi = {http://dx.doi.org/10.1016/j.physe.2012.04.008}
}
    Peng Zhao & DeSheng Liu Electronic transport properties of capped-carbon-nanotube-based molecular junctions with multiple N and B dopants

    [Abstract] [BibTeX]

    		 2012 Chinese Science Bulletin
    Vol. 57, 2073-2077     		 DOI  
    Abstract: By applying non-equilibrium Green's function in combination with density functional theory, we investigated the electronic transport properties of capped-carbon-nanotube-based molecular junctions with multiple N and B dopants. The results show that the electronic transport properties are strongly dependent on the numbers and positions of N and B dopants. Best rectifying behavior is observed in the case with one N and one B dopants, and it is deteriorated strongly with the increasing dopants. The rectifying direction is even reversed with the change of doping positions. Moreover, obvious negative differential resistance behavior at very low bias is observed in some doping cases.
    Keywords: carbon nanotube; NDR; negative differential resistance; non-equilibrium Green's function; density functional theory; ATK; Application; dopants; boron; devices; circuits
    Area: nanotubes
    BibTeX: 
    @article{Zhao2012g,
  author = {Zhao, Peng and Liu, DeSheng},
  title = {Electronic transport properties of capped-carbon-nanotube-based molecular junctions with multiple N and B dopants},
  journal = {Chinese Science Bulletin},
  publisher = {Science China Press, co-published with Springer},
  year = {2012},
  volume = {57},
  pages = {2073-2077},
  doi = {http://dx.doi.org/10.1007/s11434-012-5148-5}
}
    Qing Zhao, Yang Wang, Jianjin Dong, Lina Zhao, X.F. Rui & Dapeng Yu Nanopore-Based DNA Analysis via Graphene Electrodes

    [Abstract] [BibTeX]

    		 2012 Journal of Nanomaterials
    Vol. 2012, 318950     		 DOI  
    Abstract: We propose an improvement for nanopore-based DNA analysis via transverse transport using graphene as transverse electrodes. Our simulation results show conspicuous distinction of tunneling current during translocation of different nucleotides through nanopore. Applying the single-atom thickness property of graphene, our findings demonstrate the feasibility of using graphene as transverse electrodes in future rapid and low-cost genome sequencing.
    Keywords: ATK; Application; graphene; DNA sequencing; sensor
    Area: graphene
    BibTeX: 
    @article{Zhao2012h,
  author = {Qing Zhao and Yang Wang and Jianjin Dong and Lina Zhao and X. F. Rui and Dapeng Yu},
  title = {Nanopore-Based DNA Analysis via Graphene Electrodes},
  journal = {Journal of Nanomaterials},
  year = {2012},
  volume = {2012},
  pages = {318950},
  doi = {http://dx.doi.org/10.1155/2012/318950}
}
    Ganhong Zheng, Zhenxiang Dai, Yanyan Zhang, Yuqin Dong, Yongqing Ma & Guang Li Molecular rectification of thiol-linked Au|PTCDI-[CH2]n|Au junctions

    [Abstract] [BibTeX]

    		 2012 Solid State Communications
    Vol. 152(16), 1535-1540     		 DOI  
    Abstract: The electronic transport properties of the PTCDI-[CH2]n (0<=n<=6) molecular junctions with different molecular lengths are theoretically investigated via the first-principles density functional theory (DFT) and non-equilibrium Green's function (NEGF) method. Our results show that the transport properties depend on molecular lengths. The equilibrium conductance of the probed systems decreases exponentially with the increasing number n of the CH2 unit. With n>=1, the rectifying effect has been found. In the n=6 case, a significant rectification ratio of 72.6 is achieved at the bias of ±2.1 V in our probed voltage range. The rectification effect arises from asymmetric molecular structures. Our results suggest these molecules have great potential application in the molecular-scale device.
    Keywords: ATK; Application; molecular electronics; electrical rectification; charge transport; rectifier; diimide; molecular lengths
    Area: molecular electronics
    BibTeX: 
    @article{Zheng2012a,
  author = {Zheng, Ganhong and Dai, Zhenxiang and Zhang, Yanyan and Dong, Yuqin and Ma, Yongqing and Li, Guang},
  title = {Molecular rectification of thiol-linked Au|PTCDI-[CH2]n|Au junctions},
  journal = {Solid State Communications},
  year = {2012},
  volume = {152},
  number = {16},
  pages = {1535--1540},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.06.001}
}
    Yan hong Zhou, Ling zhi Yuan & Xiao hong Zheng Ab initio study of the transport properties of a light-driven switching molecule azobenzene substituent

    [Abstract] [BibTeX]

    		 2012 Computational Materials Science
    Vol. 61(0), 145-149     		 DOI URL 
    Abstract: A first-principles computational approach is applied to study the transport properties of a light-sensitive molecular switch. The molecule of azobenzene substituent can convert between a trans and a cis configuration upon photoexcitation, which is the basis of the switch. The current-voltage (I-V) curves of the two configuration systems vary dramatically. The current across the cis configuration system is much bigger than that across the trans configuration in a rather wide applied bias window. The ON:OFF current ratio is bigger than 27 at the bias range [-1.3, -1.9] V and [1.6, 2.4] V and reaches 107 at the bias voltage -1.7 V. A detailed analysis of the projected density of states of the two configurations in the environment of two Al (100) nanoscale electrodes and the transmission spectra of the system reveals the mechanism of the switch.
    Keywords: Light-sensitive molecular switch; Projected density of states; First-principles; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Zhou2012a,
  author = {Zhou, Yan-hong and Yuan, Ling-zhi and Zheng, Xiao-hong},
  title = {Ab initio study of the transport properties of a light-driven switching molecule azobenzene substituent},
  journal = {Computational Materials Science},
  year = {2012},
  volume = {61},
  number = {0},
  pages = {145--149},
  url = {http://www.sciencedirect.com/science/article/pii/S0927025612002388},
  doi = {http://dx.doi.org/10.1016/j.commatsci.2012.04.024}
}
    Ruiping Zhou Structural And Electronic Properties of Two-Dimensional Silicene, Graphene, and Related Structures

    [Abstract] [BibTeX]

    		 2012 School: Wright State University, Electrical Engineering, Dayton, OH, USA  URL 
    Abstract: Traditional CMOS (complementary metal-oxide-semiconductor) transistors have already been in the nanometer range. As bulk silicon material is approaching its physical limits, it is highly desirable to seek novel, functional materials to continue Moore's law. Two-dimensional(2D) materials, such as graphene and silicene, have attracted great attention since they were envisioned a few years ago, having extraordinary electrical properties. Research in this work was focused on understanding the structural and electronic properties of a few atomic layers of carbon (graphene) and silicon (silicene). Atomic structures of the 2D materials, corresponding band structures, and transport properties were calculated based on density functional theory. Band gap was observed in AB forwardly-stacked bilayer silicene with proper layer distance. Applying an external electric field resulted in further opening of the band gap up to 0.19 eV. In addition, transmission spectrum and I-V curves were calculated. A new structure of a thin silicon layer on graphene substrate is proposed, showing different transport properties from 2D silicene.
    Keywords: silicene; graphene; ATK; Application
    Area: graphene
    BibTeX: 
    @mastersthesis{Zhou2012b,
  author = {Zhou, Ruiping},
  title = {Structural And Electronic Properties of Two-Dimensional Silicene, Graphene, and Related Structures},
  school = {Wright State University, Electrical Engineering, Dayton, OH, USA},
  year = {2012},
  url = {http://etd.ohiolink.edu/view.cgi/Zhou%20Ruiping.pdf?wright1341867892}
}
    P.A. Gowri Sankar & K. Udhaya Kumar Mechanical and Electrical Properties of Single Walled Carbon Nanotubes: A Computational Study

    [Abstract] [BibTeX]

    		 2011 European Journal of Scientific Research
    Vol. 60(3), 324-340     		 URL 
    Abstract: Over the recent years, numerical modelling and computer based simulation of the properties of carbon nanotubes have become the focal points of research in computational nano-science. In this paper, we present the computational studies about the mechanical and transport properties of armchair (4, 4) and zigzag (4, 0) single walled carbon nanotubes (SWCNT). Unlike other materials, carbon nanotubes are so small that changes in structure can affect the Young's modulus. Young's modulus for an armchair single-wall carbon nanotube and zigzag single-wall carbon nanotube are calculated using an atomistic
    approach and density functional theory (DFT). Atomic forces and total energies for strained carbon nanotube segments are computed using Atomistix's Virtual NanoLab (VNL) and ToolKit (ATK) software. For a maximum strain of one percent, elastic moduli are calculated using both force-strain and energy-strain data. The average values found for Young's modulus are in the range 1.8 to 4.17 TPa depending on the cross-sectional area taken for the carbon nanotube and the calculation method used. This is in good agreement with recent experimental findings. By using ab initio density functional theory (DFT) and non-equilibrium green function approach (NEGF), the structural and electronic properties such as electronic band structure, density of states (DOS) and transmission spectrum of the single walled carbon nanotube (SWCNT) are investigated. The results suggest a wide range for practical applications, such as NEMS, acoustic sensors and nano actuators.
    Keywords: SWCNTs; DFT; NEGF; Young's modulus; band gap; nanotube; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Sankar2011,
  author = {P. A. Gowri Sankar and K. Udhaya Kumar},
  title = {Mechanical and Electrical Properties of Single Walled Carbon Nanotubes: A Computational Study},
  journal = {European Journal of Scientific Research},
  year = {2011},
  volume = {60},
  number = {3},
  pages = {324-340},
  url = {http://www.eurojournals.com/EJSR_60_3.htm}
}
    Yingying Zhang, Feng-Chao Wang & Ya-Pu Zhao Negative differential resistance behavior of silicon monatomic chain encapsulated in carbon nanotubes

    [Abstract] [BibTeX]

    		 2012 Computational Materials Science
    Vol. 62(0), 87-92     		 DOI  
    Abstract: Using nonequilibrium Green's functions in combination with density-functional theory (DFT), we investigated the electronic transport properties of the silicon monatomic chains (SiMCs) with different geometries which were induced by the encapsulation of the carbon nanotubes (CNTs). The encapsulated SiMCs, which were put inside (5,5), (6,6), (7,7) and (8,8) hydrogenated armchair CNTs, were coupled to two Au (100) nanoscale electrodes. The electronic transport property of an isolated finite SiMC was also studied to serve as a reference to our calculations. As the diameter of CNTs increases, the geometry structures of SiMCs changed. Calculated results show that the current-voltage (I-V) characteristics depend sensitively on the geometry structures of SiMCs and can be controlled by the size-selective encapsulation. Negative differential resistance (NDR) phenomena were observed within certain bias voltage ranges. A detailed analysis of the origin of NDR was carried out with the transmission spectrum, the spatial distribution of frontier molecular orbitals and the molecular projected self-consistent Hamiltonian (MPSH) states taken into consideration. These results indicated that the size-selective encapsulation of SiMCs in CNTs can become a possible candidate for designing the silicon-based nanoelectronic devices.
    Keywords: field-effect transistors; nanowires; simulations; silicon monatomic chain; size-selective encapsulation; electronic transport properties; negative differential resistance; NDR; transmission spectrum; nanotubes; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Zhang2012b,
  author = {Zhang, Yingying and Wang, Feng-Chao and Zhao, Ya-Pu},
  title = {Negative differential resistance behavior of silicon monatomic chain encapsulated in carbon nanotubes},
  journal = {Computational Materials Science},
  year = {2012},
  volume = {62},
  number = {0},
  pages = {87--92},
  doi = {http://dx.doi.org/10.1016/j.commatsci.2012.04.050}
}
    Kamal K. Saha, Anders Blom, Kristian S. Thygesen & Branislav K. Nikolic Magnetoresistance and negative differential resistance in Ni/graphene/Ni vertical heterostructures driven by finite bias voltage: A first-principles study

    [Abstract] [BibTeX]

    		 2012 Phys. Rev. B
    Vol. 85(18), 184426     		 DOI  
    Abstract: Using the nonequilibrium Green's function formalism combined with density functional theory, we study finite bias quantum transport in Ni/Gr[n]/Ni vertical heterostructures where n graphene layers are sandwiched between two semi-infinite Ni(111) electrodes. We find that the recently predicted "pessimistic" magnetoresistance of 100% for n>=5 junctions at zero bias voltage Vb->0 persists up to Vb~0.4 V, which makes such devices promising for spin-torque-based device applications. In addition, for parallel orientations of the Ni magnetizations, the n=5 junction exhibits a pronounced negative differential resistance as the bias voltage is increased from Vb=0 V to Vb~0.5 V. We confirm that both of these nonequilibrium transport effects hold for different types of bonding of Gr on the Ni(111) surface while maintaining Bernal stacking between individual Gr layers.
    Keywords: ATK; Application; graphene; magneto-tunnel resistance; TMR; Nickel surface; NDR; negative differential resistance; MTJ;
    Area: graphene; spin; nvm
    BibTeX: 
    @article{Saha2012a,
  author = {Saha, Kamal K. and Blom, Anders and Thygesen, Kristian S. and Nikolic, Branislav K.},
  title = {Magnetoresistance and negative differential resistance in Ni/graphene/Ni vertical heterostructures driven by finite bias voltage: A first-principles study},
  journal = {Phys. Rev. B},
  publisher = {American Physical Society},
  year = {2012},
  volume = {85},
  number = {18},
  pages = {184426},
  doi = {http://dx.doi.org/10.1103/PhysRevB.85.184426}
}
    Y.H. Chen, C.M. Zhang, J.B. Wu & Q. Lin Effect of O/N Substitutive Doping on the Band Structure and Transport Properties of the zigzag Boron Nitride Narrow-Nanoribbons

    [Abstract] [BibTeX]

    		 2012 Acta Physico-chimica Sinica
    Vol. 28(3), 567-572     		 DOI  
    Abstract: By performing first-principles calculations and non-equilibrium Green's function, the energy band structure, transmission spectrum and current voltage characteristics of the O-doping zigzag boron nitride narrow-nanoribbons (z-BNNNRs) were investigated. The calculation results show that O-doping remarkably changes the z-BNNNRs energy band structure and transform the material from a semiconductor to a metal. It is also demonstrated that the system exhibits an obvious negative differential resistance (NDR) characteristic. Further investigations revealed that the position and concentration of O-doping also affected the NOR behavior over a certain range of bias. The negative differential conductance (NDC) for edge-doping is greater than that for middle-doping and the maximum of the NDC increases with an increase of the concentration of O-doping. This special electronic transport property of O-doping z-BNNNRs makes it more suitable as a candidate for molecular devices.
    Keywords: BN nanoribbon; O-doping; energy band structure; transport property; negative differential resistance; NRD; armchair graphene nanoribbons; electronic-structure; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Chen2012,
  author = {Chen, Y. H. and Zhang, C. M. and Wu, J. B. and Lin, Q.},
  title = {Effect of O/N Substitutive Doping on the Band Structure and Transport Properties of the zigzag Boron Nitride Narrow-Nanoribbons},
  journal = {Acta Physico-chimica Sinica},
  year = {2012},
  volume = {28},
  number = {3},
  pages = {567--572},
  doi = {http://dx.doi.org/10.3866/PKU.WHXB201112071}
}
    P.J. Mohan, V.P. Georgiev & J.E. McGrady Periodic trends in electron transport through extended metal atom chains: comparison of Ru-3(dpa)(4)(NCS)(2) with its first-row analogues

    [Abstract] [BibTeX]

    		 2012 Chemical Science
    Vol. 3(4), 1319-1329     		 DOI  
    Abstract: Density functional theory is used to reconcile the structural, magnetic and electron transport properties of a triruthenium extended metal atom chain, Ru-3(dpa)(4)(NCS)(2). The distinct bending of the Ru-Ru-Ru core in this species is traced to strong second-order mixing between levels of sigma and pi symmetry that are near degenerate in the linear geometry. The dominant electron transport channel is formed by the LUMO, an orbital of pi* symmetry that lies just above the Fermi level of the gold electrode. The bending has a substantial impact on electron transport in that it induces a spin crossover from a quintet to a singlet which in turn brings the LUMO much closer to the Fermi level. The presence of significant net pi bonding in the metal chains also broadens the pi/pi(nb)/pi* manifold, such that the channel is not strongly perturbed by the electric field, even at a bias of 1.0 V. The presence of a robust pi symmetry conduction channel marks the triruthenium systems out as quite distinct from its first-row counterparts, Cr-3(dpa)(4)(NCS)(2) and Co-3(dpa)(4)(NCS)(2), where current flows primarily through the sigma framework.
    Keywords: bond-stretch isomerism; regular 2-component Hamiltonians; linear trimetallic complexes; molecular wire; transition-metal; string complexes; carbon nanotubes; ab-initio; electrochemical properties; magnetic-properties; ATK; Application; spin
    Area: molecular electronics; spin
    BibTeX: 
    @article{Mohan2012,
  author = {Mohan, P. J. and Georgiev, V. P. and McGrady, J. E.},
  title = {Periodic trends in electron transport through extended metal atom chains: comparison of Ru-3(dpa)(4)(NCS)(2) with its first-row analogues},
  journal = {Chemical Science},
  year = {2012},
  volume = {3},
  number = {4},
  pages = {1319--1329},
  doi = {http://dx.doi.org/10.1039/c2sc01024k}
}
    Cai Juan Xia, Han Chen Liu & Ying Tang Zhang Theory of the Rectifying Performance in Molecular Device: The Role of Anchoring Groups

    [Abstract] [BibTeX]

    		 2012 Solid State Phenomena
    Vol. 181-182, 344-347     		 DOI  
    Abstract: The electronic transport of the single molecule via different anchoring groups is studied using density functional theory in conjunction with the nonequilibrium Green's function. The results show that the electronic transport properties are strongly dependent on the anchoring groups. Asymmetric electrical response for opposite biases is observed resulting in significant rectification in current. The transmission coefficients and spatial distributions of molecular orbitals under various external biases voltage are analyzed, and it suggests that the asymmetry of the coupling between the molecule and the electrodes with external bias leads to rectifying performance.
    Keywords: anchoring groups; density functional theory (DFT); electronic transport; nonequilibrium Green's function; rectification; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Xia2012b,
  author = {Cai Juan Xia and Han Chen Liu and Ying Tang Zhang},
  title = {Theory of the Rectifying Performance in Molecular Device: The Role of Anchoring Groups},
  journal = {Solid State Phenomena},
  year = {2012},
  volume = {181-182},
  pages = {344-347},
  doi = {http://dx.doi.org/10.4028/www.scientific.net/SSP.181-182.344}
}
    Cai Juan Xia, Ying Tang Zhang & Xue Jun Zai Negative Differential Resistance Induced by Intermolecular Interaction in Molecular Device

    [Abstract] [BibTeX]

    		 2012 Solid State Phenomena
    Vol. 181-182, 312-315     		 DOI  
    Abstract: Based on nonequilibrium Green's function and first-principles calculation, we investigate the transport properties of the molecule device with a donor-acceptor molecular complex sandwiched between two electrodes. Numerical results show that a negative differential resistance under applied bias can be observed. The mechanism of negative differential resistance is mainly induced by the orbital match of molecule and electrodes as well as intermolecular charge transfer.
    Keywords: density functional theory (DFT); electronic transport; negative differential resistance; NDR; non-equilibrium Green's function; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Xia2012c,
  author = {Cai Juan Xia and Ying Tang Zhang and Xue Jun Zai},
  title = {Negative Differential Resistance Induced by Intermolecular Interaction in Molecular Device},
  journal = {Solid State Phenomena},
  year = {2012},
  volume = {181-182},
  pages = {312-315},
  doi = {http://dx.doi.org/10.4028/www.scientific.net/SSP.181-182.312}
}
    H.P. Xiao, Zhizhou Yu, M.L. Hu, X.Y. Peng, L.Z. Sun & Jianxin Zhong Zigzag graphene nanoribbons: Flexible and robust transparent conductors

    [Abstract] [BibTeX]

    		 2012 Solid State Sciences
    Vol. 14(6), 711-714     		 DOI  
    Abstract: We report the effect of bending deformation on the optical and transport properties of zigzag graphene nanoribbons (ZGNRs) induced by the uniaxial strain using the first-principles method combined with non-equilibrium Green's function. The optical properties of ZGNRs in the region of visible light are almost unchanged under the uniaxial strain, whereas an absorption peak occurs at the infrared region for the bent ZGNRs under the transverses strain. The transport properties of ZGNRs under the transverses strain with the bending angle up to 65 degrees remain almost the same as those of the flat one. The transmission coefficients around the Fermi level only slightly decrease when the bending angle further increases to 72.5 degrees. Moreover, ZGNRs under the longitudinal strain show the same transmission conductance around the Fermi level as that of the flat one. The edge states of ZGNRs still behave as excellent ballistic transport channels under bending deformation, which makes them promising flexible and robust transparent conductors.
    Keywords: total-energy calculations; carbon nanotube films; wave basis-set; semiconductors; oxide; form; graphene nanoribbon; bending deformation; optical property; transport property; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Xiao2012,
  author = {Xiao, H.P. and Yu, Zhizhou and Hu, M.L. and Peng, X.Y. and Sun, L.Z. and Zhong, Jianxin},
  title = {Zigzag graphene nanoribbons: Flexible and robust transparent conductors},
  journal = {Solid State Sciences},
  year = {2012},
  volume = {14},
  number = {6},
  pages = {711--714},
  doi = {http://dx.doi.org/10.1016/j.solidstatesciences.2012.03.027}
}
    Zhi-Qiang Fan & Xie Fang Effect of B and N doping on the negative differential resistance in molecular device

    [Abstract] [BibTeX]

    		 2012 Acta Phys. Sin.
    Vol. 61(7), 077303     		 URL 
    Abstract: By using nonequilibrium Green's functions in combination with the density-functional theory, we investigate the effects of B and N doping on the transport properties in phenalenyl molecular device. The calculated results show that negative differential resistance behavior can be observed in phenalenyl molecular device where the device current can decrease with the base voltage increasing particularly in a bias voltage region, and the peak-to-valley current ratio reaches up to 5.12. The device current can be increased before 0.8 V when the molecular center atom is replaced by B or N atom. But, the negative differential resistance behavior can be weakened and the peak-to-valley current ratio can decrease to 3.83 and 3.61, respectively. The doping effects of B and N, which are induced by the difference in extranuclear electron number between them, can make the orbitals and corresponding transmission peaks move toward high or low energy to modulate the electronic transport ability and the negative differential resistance behavior of the device.
    Keywords: ATK; Application; molecular electronics; doping; nonequilibrium Green's functions; density-functional theory; electronic transport; negative differential resistance behavior;
    Area: molecular electronics
    BibTeX: 
    @article{Fan2012a,
  author = {Fan, Zhi-Qiang and Xie Fang},
  title = {Effect of B and N doping on the negative differential resistance in molecular device},
  journal = {Acta Phys. Sin.},
  year = {2012},
  volume = {61},
  number = {7},
  pages = {077303},
  url = {http://wulixb.iphy.ac.cn/EN/abstract/abstract47220.shtml}
}
    Jun He, Ke-Qiu Chen & Chang Q. Sun The weak pi-pi interaction originated resonant tunneling and fast switching in the carbon based electronic devices

    [BibTeX]

    		 2012 AIP Advances
    Vol. 2(1), 012137     		 DOI  
    Keywords: density functional theory; fullerene devices; fullerenes; Green's function methods; negative resistance; resonant tunnelling; ATK; Application
    Area: fullerenes
    BibTeX: 
    @article{He2012a,
  author = {Jun He and Ke-Qiu Chen and Chang Q. Sun},
  title = {The weak pi-pi interaction originated resonant tunneling and fast switching in the carbon based electronic devices},
  journal = {AIP Advances},
  publisher = {AIP},
  year = {2012},
  volume = {2},
  number = {1},
  pages = {012137},
  doi = {http://dx.doi.org/10.1063/1.3685777}
}
    Kenji Toyoda Theoretical Investigation of Chemical Spin Doping into Single Porphyrin Junctions toward Ultrahigh-Sensitive Nitric Oxide Sensor

    [Abstract] [BibTeX]

    		 2012 Japanese Journal of Applied Physics
    Vol. 51(4), 045202     		 DOI  
    Abstract: We theoretically study chemical spin doping into single porphyrins connected to nanoelectrodes via benzenethiols, ethynyl-benzenethiols, and vinyl-benzenethiols using the adsorption of a nitric oxide (NO) molecule. For all three anchoring groups, the adsorption of a NO molecule injects one spin into single-molecule junctions and produces antiferromagnetic interactions between the injected spin and the original spins at the junctions, resulting in a decrease in the spin-polarized currents. We found that the magnitude of change in the spin-polarized current significantly depends on the type of anchoring groups; the magnitude is ordered by the following anchoring group: vinyl-benzenethiol > ethynyl-benzenethiol > benzenethiol. In particular, for vinyl-benzenethiol, spin doping causes not only pi electron localization on molecular orbitals but also structural change.
    Keywords: ATK; Application; sensor; molecular electronics; molecular spintronics; transport properties; conductance; devices; wires
    Area: molecular electronics; spin
    BibTeX: 
    @article{Toyoda2012,
  author = {Toyoda, Kenji},
  title = {Theoretical Investigation of Chemical Spin Doping into Single Porphyrin Junctions toward Ultrahigh-Sensitive Nitric Oxide Sensor},
  journal = {Japanese Journal of Applied Physics},
  year = {2012},
  volume = {51},
  number = {4},
  pages = {045202},
  doi = {http://dx.doi.org/10.1143/JJAP.51.045202}
}
    Cai-Juan Xia, De-Sheng Liu, De-Hua Zhang & Han-Chen Liu Theoretical Studies of the Rectifying Performance In Diblock Molecular Junctions: the Role of the Anchoring Groups

    [Abstract] [BibTeX]

    		 2012 International Journal of Modern Physics B
    Vol. 26(11), 1250082     		 DOI  
    Abstract: By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the effect of different anchoring groups on the rectifying behavior in diblock molecular junctions. The spatial distributions of molecular orbitals and the influence of transmission coefficients under various external voltage biases on the electronic transport through the molecular device are discussed in detail. The results show that the anchoring groups play a significant role on the electronic transport properties. The rectifying performance in molecular junctions can be manipulated, enhanced, or suppressed by a careful consideration of the effects of the anchoring group and such modifications become crucial in optimizing the electronic transport properties of chemical structures.
    Keywords: ATK; Application; molecular electronics; rectifying performance; nonequilibrium green's function; electronic transport; density functional theory; single-molecule; conductance; switch; electronics; diodes
    Area: molecular electronics
    BibTeX: 
    @article{Xia2012a,
  author = {Xia, Cai-Juan and Liu, De-Sheng and Zhang, De-Hua and Liu, Han-Chen},
  title = {Theoretical Studies of the Rectifying Performance In Diblock Molecular Junctions: the Role of the Anchoring Groups},
  journal = {International Journal of Modern Physics B},
  year = {2012},
  volume = {26},
  number = {11},
  pages = {1250082},
  doi = {http://dx.doi.org/10.1142/S0217979212500828}
}
    Z.Q. Bai, Y.H. Lu, L. Shen, V. Ko, G.C. Han & Y.P. Feng Transport properties of high-performance all-Heusler Co[sub 2]CrSi/Cu[sub 2]CrAl/Co[sub 2]CrSi giant magnetoresistance device

    [Abstract] [BibTeX]

    		 2012 Journal of Applied Physics
    Vol. 111(9), 093911     		 DOI  
    Abstract: Transport properties of giant magnetoresistance (MR) junction consisting of trilayer Co2CrSi/Cu2CrAl/Co2CrSi Heusler alloys (L21) are studied using first-principles approach based on density functional theory and the non-equilibrium Green's function method. Highly conductive channels are found in almost the entire k-plane when the magnetizations of the electrodes are parallel, while they are completely blocked in the antiparallel configuration, which leads to a high magnetoresistance ratio (the pessimistic MR ratio is nearly 100%). Furthermore, the calculated I-V curve shows that the device behaves as a good spin valve with a considerable disparity in currents under the parallel and antiparallel magnetic configurations of the electrodes. The Co2CrSi/Cu2CrAl/Co2CrSi junction could be useful for high-performance all-metallic current-perpendicular-to-plane giant magnetoresistance reading head for the next generation high density magnetic storage.
    Keywords: ab initio calculations; aluminium alloys; chromium alloys; cobalt alloys; copper alloys; density functional theory; electrodes; giant magnetoresistance; Green's function methods; magnetic storage; silicon alloys; spin valves; ATK; Application; spin; MTJ
    Area: interfaces; spin; nvm
    BibTeX: 
    @article{Bai2012a,
  author = {Z. Q. Bai and Y. H. Lu and L. Shen and V. Ko and G. C. Han and Y. P. Feng},
  title = {Transport properties of high-performance all-Heusler Co[sub 2]CrSi/Cu[sub 2]CrAl/Co[sub 2]CrSi giant magnetoresistance device},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2012},
  volume = {111},
  number = {9},
  pages = {093911},
  doi = {http://dx.doi.org/10.1063/1.4712301}
}
    Sun Young Baik, Yong Jae Cho, Young Rok Lim, Hyung Soon Im, Dong Myung Jang, Yoon Myung, Jeunghee Park & Hong Seok Kang Charge-Selective Surface-Enhanced Raman Scattering Using Silver and Gold Nanoparticles Deposited on Silicon-Carbon Core-Shell Nanowires

    [Abstract] [BibTeX]

    		 2012 ACS Nano
    Vol. 6(3)ACS Nano, 2459-2470     		 DOI  
    Abstract: The deposition of silver (Ag) or gold (Au) nanoparticles (NPs) on vertically aligned silicon-carbon (Si-C) core-shell nanowires (NWs) produces sensitive substrates for surface-enhanced Raman spectroscopy (SERS). The undoped and 30% nitrogen (N)-doped graphitic layers of the C shell (avg thickness of 20 nm) induce a higher sensitivity toward negatively (-) and positively (+) charged dye molecules, respectively, showing remarkable charge selectivity. The Ag NPs exhibit higher charge selectivity than the Au NPs. The Ag NPs deposited on p- and n-type Si NWs also exhibit (-) and (+) charge selectivity, respectively, which is higher than that of the Au NPs. The X-ray photoelectron spectroscopy analysis indicates that the N-doped graphitic layers donate more electrons to the metal NPs than the undoped ones. More distinct electron transfer occurs to the Ag NPs than to the Au NPs. First principles calculations of the graphene-metal adducts suggest that the large electron transfer capacity of the N-doped graphitic layers is due to the formation of a N->Ag coordinate bond involving the lone pair electrons of the N atoms. We propose that the more (-) charged NPs on the N-doped graphitic layers prefer the adsorption of (+) charged dyes, enhancing the SERS intensity. The charge selectivity of the Si NW substrates can also be rationalized by the greater electron transfer from the n-type Si to the metal NPs.
    Keywords: ATK; Application; surface-enhanced Raman scattering; charge selectivity; N-doped graphitic layers; silicon nanowires; silver nanoparticles; first principles calculations; electron transfer
    Area: nanowires
    BibTeX: 
    @article{Baik2012,
  author = {Baik, Sun Young and Cho, Yong Jae and Lim, Young Rok and Im, Hyung Soon and Jang, Dong Myung and Myung, Yoon and Park, Jeunghee and Kang, Hong Seok},
  title = {Charge-Selective Surface-Enhanced Raman Scattering Using Silver and Gold Nanoparticles Deposited on Silicon-Carbon Core-Shell Nanowires},
  booktitle = {ACS Nano},
  journal = {ACS Nano},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {6},
  number = {3},
  pages = {2459--2470},
  doi = {http://dx.doi.org/10.1021/nn204797b}
}
    Chang-Jie Dai, Xiao-Hong Yan, Yan-Dong Guo & Yang Xiao Effect of an out-of-plane cross connection on the electronic transport of zigzag graphene nanoribbon

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(26-27), 2010-2014     		 DOI  
    Abstract: Electronic transport properties of out-of-plane graphene nanoribbon intersections have been investigated by using computational method. The inter-distance between two graphene nanoribbons is found to affect the transport properties strongly and its affection can be neglected for larger ones, even under an external bias. Wider graphene nanoribbons will bring stronger interaction into the system, and result in more transmission dips. Moreover, the stacking configuration between two graphene nanoribbons is found to be crucial for the electronic transport under an external bias, as it can affect the electronic transport strongly near the charge neutral point.
    Keywords: graphene nanoribbon; cross connection; electronic transport; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Dai2012,
  author = {Dai, Chang-Jie and Yan, Xiao-Hong and Guo, Yan-Dong and Xiao, Yang},
  title = {Effect of an out-of-plane cross connection on the electronic transport of zigzag graphene nanoribbon},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {26-27},
  pages = {2010--2014},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.04.054}
}
    Xiaoqing Deng, Guiping Tang & Chao Guo Tuning the electronic transport properties for a trigonal graphene flake

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(23), 1839-1844     		 DOI URL 
    Abstract: By applying nonequilibrium Green's functions in combination with density-functional theory, we have investigated the effects of two side groups, NH2 and NO2, on the electronic transport properties of the trigonal graphene flake. It has been found that the rectifying ratios (RR) and direction can be significantly tuned by the type and the attached positions of side groups. The NH2 group shows an obvious electron-donating characteristic, whereas NO2 group demonstrates a poorly electron-accepting behavior in these systems. The analysis on the spatial distribution and the energy level of frontier orbitals, transmission spectra, and electrostatic potential distribution give an inside view of the observed results.
    Keywords: Electronic transport; Graphene quantum dot; Density-functional theory; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Deng2012a,
  author = {Deng, Xiaoqing and Tang, Guiping and Guo, Chao},
  title = {Tuning the electronic transport properties for a trigonal graphene flake},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {23},
  pages = {1839--1844},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960112004665},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.04.021}
}
    Neeraj K. Jaiswal & Pankaj Srivastava Ab-Initio Study of Transition Metal (Ni) Interaction with Zigzag Graphene Nanoribbons

    [Abstract] [BibTeX]

    		 2012 Journal of Computational and Theoretical Nanoscience
    Vol. 9(4), 555-559     		 DOI  
    Abstract: We have performed a systematic study to investigate how transition metal (TM) atoms affect the electronic properties of zigzag graphene nanoribbons (ZGNR). We considered the interaction of ZGNR and TM taking Ni as a terminating element as well as a substitutional dopant at single vacancy sites. Present calculations revealed that all the considered ribbons have ferromagnetic ground state. The calculated binding energy varies from -6.86 eV to -10.55 eV for Ni-termination and -4.07 eV to -10.35 eV for Ni-doping that shows a rather strong binding. The present calculations revealed that edge doped ribbons are energetically more favourable than the center doping. Ni-termination enhances the metallicity with a little distortion in the characteristics band structure of ZGNR whereas in Ni-doping, the characteristics band structure is lost and a dispersive band appears at Fermi level. The position of this dispersive band is independent of the ribbon width and thus equalizing the metallicity in ZGNR. Width independent metallicity is crucial at nano regime.
    Keywords: graphene nanoribbon; ATK; Application; binding energy; electronic band structure; spin
    Area: graphene; spin
    BibTeX: 
    @article{Jaiswal2012,
  author = {Jaiswal, Neeraj K. and Srivastava, Pankaj},
  title = {Ab-Initio Study of Transition Metal (Ni) Interaction with Zigzag Graphene Nanoribbons},
  journal = {Journal of Computational and Theoretical Nanoscience},
  year = {2012},
  volume = {9},
  number = {4},
  pages = {555-559},
  doi = {http://dx.doi.org/10.1166/jctn.2012.2060}
}
    Xinqian Li, Aleksandar Staykov & Kazunari Yoshizawa Orbital Views on Electron-Transport Properties of Cyclophanes: Insight into Intermolecular Transport:

    [Abstract] [BibTeX]

    		 2012 Bulletin of the Chemical Society of Japan
    Vol. 85(2), 181-188     		 DOI  
    Abstract: Electron-transport properties of cyclophanes are investigated with qualitative Hückel molecular orbital analysis for better understanding of the intermolecular interaction in molecular devices. Charge and electron transfers often take place via through-space interactions, which are observed both in large biological molecules and in organic molecular crystals. Since the intermolecular electronic coupling in pi-stacked structures plays an important role in total device performance, in this work [2,2]paracyclophane is studied to investigate the effect of the intermolecular interactions in aromatic hydrocarbons on its electron-transport properties. According to the orbital symmetry rule, the symmetry-allowed and symmetry-forbidden connections for electron transport between the benzene rings are predicted just from the phase and amplitude of the frontier orbitals. The meta connection is symmetry allowed for electron transport while the para and ortho connections are symmetry forbidden. The qualitative predictions made with the Hückel approximation are found consistent with the calculation results obtained with density functional theory. The qualitative but essential understanding in the orbital views would extend the application of the rule from a single molecule to a crystal structure for the development of high-performance molecular devices.
    Keywords: ATK-SE; Application; molecular electronics; orbital view;
    Area: molecular electronics
    BibTeX: 
    @article{Li2012d,
  author = {Li, Xinqian and Staykov, Aleksandar and Yoshizawa, Kazunari},
  title = {Orbital Views on Electron-Transport Properties of Cyclophanes: Insight into Intermolecular Transport: },
  journal = {Bulletin of the Chemical Society of Japan},
  year = {2012},
  volume = {85},
  number = {2},
  pages = {181--188},
  doi = {http://dx.doi.org/10.1246/bcsj.20110256}
}
    Ming-Jun Li, Hui Xu, Ke-Qiu Chen & Meng-Qiu Long Electronic transport properties in benzene-based heterostructure: Effects of anchoring groups

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(20), 1692-1697     		 DOI URL 
    Abstract: Using density functional theory (DFT) combined with nonequilibrium Green's functions (NEGF), the electronic transport properties of benzene-based heterostructure molecular devices have been investigated. We focus on the contact geometry between molecules and electrodes, and several different anchoring groups have been considered. The current-voltage characteristics were calculated for positive and negative bias voltages, and discussed in terms of transmission spectra, transferred charges, and molecular projected self-consistent Hamiltonian (MPSH) states. Our results show that the anchoring groups play a crucial role in determining the overall conductivity of the molecular devices. Negative differential resistance (NDR) and rectifying effect can be observed.
    Keywords: anchoring group; transport property; rectifying effect; NDR behavior; molecular junctions; room-temperature; carbon nanotube; conductance; devices; 1st-principles; rectification; transistors; rectifiers; film; negative differential resistance; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Li2012e,
  author = {Li, Ming-Jun and Xu, Hui and Chen, Ke-Qiu and Long, Meng-Qiu},
  title = {Electronic transport properties in benzene-based heterostructure: Effects of anchoring groups},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {20},
  pages = {1692--1697},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960112004094},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.03.061}
}
    Yong-Jun Li, Qing-Qing Sun, Lin Chen, Peng Zhou, Peng-Fei Wang, Shi-Jin Ding & David Wei Zhang Hexagonal boron nitride intercalated multi-layer graphene: a possible ultimate solution to ultra-scaled interconnect technology

    [Abstract] [BibTeX]

    		 2012 AIP Advances
    Vol. 2(1), 012191     		 DOI  
    Abstract: We proposed intercalation of hexagonal boron nitride (hBN) in multilayer graphene to improve its performance in ultra-scaled interconnects for integrated circuit. The effect of intercalated hBN layer in bilayer graphene is investigated using non-equilibrium Green's functions. We find the hBN intercalated bilayer graphene exhibit enhanced transport properties compared with pristine bilayer ones, and the improvement is attributed to suppression of interlayer scattering and good planar bonding condition of inbetween hBN layer. Based on these results, we proposed a via structure that not only benefits from suppressed interlayer scattering between multilayer graphene, but also sustains the unique electrical properties of graphene when many graphene layers are stacking together. The ideal current density across the structure can be as high as 4.6×10^9 A/cm^2 at 1 V, which is very promising for the future high-performance interconnect.
    Keywords: boron compounds; current density; electrical conductivity; graphene; Green's function methods; III-V semiconductors; intercalation compounds; multilayers; semiconductor-insulator boundaries; wide band gap semiconductors ; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Li2012f,
  author = {Li, Yong-Jun and Sun, Qing-Qing and Chen, Lin and Zhou, Peng and Wang, Peng-Fei and Ding, Shi-Jin and Zhang, David Wei},
  title = {Hexagonal boron nitride intercalated multi-layer graphene: a possible ultimate solution to ultra-scaled interconnect technology},
  journal = {AIP Advances},
  publisher = {AIP},
  year = {2012},
  volume = {2},
  number = {1},
  pages = {012191},
  doi = {http://dx.doi.org/10.1063/1.3701267}
}
    Wenhu Liao, Heping Zhao, Gang Ouyang, Ke-Qiu Chen & Guanghui Zhou Symmetry of atomistic structure for armchair-edge graphene nanoribbons under uniaxial strain

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(15), 153112     		 DOI  
    Abstract: We present a systematic first-principles calculation on the atomistic structural variation for armchair-edge graphene nanoribbons (AGNRs) under a small planar uniaxial strain along armchair and zigzag directions, respectively. Interestingly, it is found that asymmetric AGNRs are more sensitive to the external strain with more types of carbon-carbon bonds and angles, while symmetric ones show less types of bonds and angles under the same strain. This difference is attributed to the symmetric property of AGNRs combining with the bond theory. Our findings may be useful in further understanding of GNRs under strain and in designing nanoelectromechanical devices based on GNRs.
    Keywords: ab initio calculations; bonds (chemical); graphene; nanoribbons; stress-strain relations ; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Liao2012,
  author = {Liao, Wenhu and Zhao, Heping and Ouyang, Gang and Chen, Ke-Qiu and Zhou, Guanghui},
  title = {Symmetry of atomistic structure for armchair-edge graphene nanoribbons under uniaxial strain},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {15},
  pages = {153112},
  doi = {http://dx.doi.org/10.1063/1.3702842}
}
    Y. Min, J.H. Fang, C.G. Zhong & K.L. Yao Rectification effect about vacuum separating carbon nanotube bundle predicted by first-principles study

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(23), 1845-1848     		 DOI URL 
    Abstract: For the molecular spintronics transport systems, we propose that the spin current rectifier can be constructed using the nonmagnetic lead. The proposal is confirmed according to the first-principles study of the transport characteristics of a vacuum separating (15,0) carbon nanotube bundle where only one zigzag edge is hydrogenated. The strong rectification effect for spin (charge) current is obtained in the case of the magnetic parallel (anti-parallel) configuration of two zigzag edges. Our investigations indicate that such device can be used as the spin filter and the counterpart of the p-n junction in the field of molecular electronics.
    Keywords: Non-equilibrium Green's function; Density-functional theory; Spin current; Ab initio; molecular spintronics; nanotubes; spin; MTJ; magnetoresistance; ATK; Application
    Area: nanotubes; spin; nvm
    BibTeX: 
    @article{Min2012,
  author = {Min, Y. and Fang, J.H. and Zhong, C.G. and Yao, K.L.},
  title = {Rectification effect about vacuum separating carbon nanotube bundle predicted by first-principles study},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {23},
  pages = {1845--1848},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960112004756},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.04.030}
}
    B. Sarikavak-Lisesivdin, S.B. Lisesivdin & E. Ozbay Ab initio study of Ru-terminated and Ru-doped armchair graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Molecular Physics
    Vol. 110(18)Molecular Physics, 2295-2300     		 DOI  
    Abstract: We investigate the effects of ruthenium (Ru) termination and Ru doping on the electronic properties of armchair graphene nanoribbons (AGNRs) using first-principles methods. The electronic band structures, geometries, density of states, binding energies, band gap information, and formation energies of related structures are calculated. It is well founded that the electronic properties of the investigated AGNRs are highly influenced by Ru termination and Ru doping. With Ru termination, metallic band structures with quasi-zero-dimensional, one-dimensional and quasi-one-dimensional density of states (DOS) behavior are obtained in addition to dominant one-dimensional behavior. In contrast to Ru termination, Ru doping introduces small but measurable (12.4 to 89.6 meV) direct or indirect band gaps. These results may present an additional way to produce tunable band gaps in AGNRs.
    Keywords: ATK; Application; graphene nanoribbon; electronic-properties; edges; films
    Area: graphene
    BibTeX: 
    @article{Sarikavak-Lisesivdin2012,
  author = {Sarikavak-Lisesivdin, B. and Lisesivdin, S. B. and Ozbay, E.},
  title = {Ab initio study of Ru-terminated and Ru-doped armchair graphene nanoribbons},
  booktitle = {Molecular Physics},
  journal = {Molecular Physics},
  publisher = {Taylor & Francis},
  year = {2012},
  volume = {110},
  number = {18},
  pages = {2295-2300},
  doi = {http://dx.doi.org/10.1080/00268976.2012.678905}
}
    Anurag Srivastava & Neha Tyagi High pressure behavior of AlAs nanocrystals: the first-principle study

    [Abstract] [BibTeX]

    		 2011 High Pressure Research
    Vol. 32(1)High Pressure Research, 43-47     		 DOI  
    Abstract: In this study, the first-principle density functional approach has been used to analyze the pressure-induced structural stability and phase transformation in AlAs nanocrystals. This study includes the stability analysis of AlAs nanocrystals in their B4-, B3-, B1- and B2-type phases, and we observed that the B3-type phase is the most stable. We also observed the structural transformations in AlAs nanocrystals from B3-B1 at around 8.9 GPa, B3-B2 at 7.12 GPa and B3-B4 at 3.88 GPa. The stability of the materials has been analyzed using local density approximation with the Perdew-Zunger parameterization and also with the Perdew-Burke-Ernzerhof (PBE) and revised PBE parameterizations of the generalized gradient approximation potential.
    Keywords: ATK; Application; first principle; AlAs; phase transition; nanocrystal; generalized gradient approximation; semiconductor nanocrystals; phase-transition; GaAs
    Area: semi
    BibTeX: 
    @article{Srivastava2011b,
  author = {Srivastava, Anurag and Tyagi, Neha},
  title = {High pressure behavior of AlAs nanocrystals: the first-principle study},
  booktitle = {High Pressure Research},
  journal = {High Pressure Research},
  publisher = {Taylor & Francis},
  year = {2011},
  volume = {32},
  number = {1},
  pages = {43--47},
  doi = {http://dx.doi.org/10.1080/08957959.2011.643791}
}
    Xiaojin Tan, Huijin Liu, Yanwei Wen, Hongyan Lv, Lu Pan, Jing Shi & Xinfeng Tang Optimizing the thermoelectric performance of zigzag and chiral carbon nanotubes

    [Abstract] [BibTeX]

    		 2012 Nanoscale Research Letters
    Vol. 7(1), 116     		 DOI URL 
    Abstract: Using nonequilibrium molecular dynamics simulations and nonequilibrium Green's function method, we investigate the thermoelectric properties of a series of zigzag and chiral carbon nanotubes which exhibit interesting diameter and chirality dependence. Our calculated results indicate that these carbon nanotubes could have higher ZT values at appropriate carrier concentration and operating temperature. Moreover, their thermoelectric performance can be significantly enhanced via isotope substitution, isoelectronic impurities, and hydrogen adsorption. It is thus reasonable to expect that carbon nanotubes may be promising candidates for high-performance thermoelectric materials.
    Keywords: ATK; Application; carbon nanotube; thermoelectric properties; ZT
    Area: nanotubes; thermo
    BibTeX: 
    @article{Tan2012,
  author = {Tan, Xiaojin and Liu, Huijin and Wen, Yanwei and Lv, Hongyan and Pan, Lu and Shi, Jing and Tang, Xinfeng},
  title = {Optimizing the thermoelectric performance of zigzag and chiral carbon nanotubes},
  journal = {Nanoscale Research Letters},
  year = {2012},
  volume = {7},
  number = {1},
  pages = {116},
  url = {http://www.nanoscalereslett.com/content/7/1/116},
  doi = {http://dx.doi.org/10.1186/1556-276X-7-116}
}
    Haiqing Wan, Ying Xu & Guanghui Zhou Dual conductance, negative differential resistance, and rectifying behavior in a molecular device modulated by side groups

    [Abstract] [BibTeX]

    		 2012 J. Chem. Phys.
    Vol. 136(18), 184704-6     		 DOI  
    Abstract: We investigate the electronic transport properties for a molecular device model constructed by a phenylene ethynylene oligomer molecular with different side groups embedding in a carbon chain between two graphene electrodes. Using the first-principles method, the unusual dual conductance, negative differential resistance (NDR) behavior with large peak to valley ratio, and obvious rectifying performance are numerically observed in such proposed molecular device. The analysis of the molecular projected self-consistent Hamiltonian and the evolution of the frontier molecular orbitals (MOs) as well as transmission coefficients under various external voltage biases gives an inside view of the observed results, which suggests that the dual conductance behavior and rectifying performance are due to the asymmetry distribution of the frontier MOs as well as the corresponding coupling between the molecule and electrodes. But the NDR behavior comes from the conduction orbital being suppressed at certain bias. Interestingly, the conduction properties can be tuned by introducing side groups to the molecule and the rectification as well as the NDR behavior (peak to valley ratio) can be improved by adding different side groups in the device model.
    Keywords: molecular electronics; graphene; transport-properties; electron-transport; room-temperature; carbon; rectifiers; nanowires; negative differential resistance; NDR; rectification; ATK; Application;
    Area: molecular electronics; graphene
    BibTeX: 
    @article{Wan2012,
  author = {Wan, Haiqing and Xu, Ying and Zhou, Guanghui},
  title = {Dual conductance, negative differential resistance, and rectifying behavior in a molecular device modulated by side groups},
  journal = {J. Chem. Phys.},
  publisher = {AIP},
  year = {2012},
  volume = {136},
  number = {18},
  pages = {184704--6},
  doi = {http://dx.doi.org/10.1063/1.4712615}
}
    Bin Bin Wang, Feng Chao Wang & Ya Pu Zhao Understanding formation mechanism of ZnO diatomic chain and multi-shell structure using physical mechanics: Molecular dynamics and first-principle simulations

    [Abstract] [BibTeX]

    		 2012 Science China - Physics, Mechanics & Astronomy
    Vol. 55(6), 1138-1146     		 DOI  
    Abstract: In this paper, the possibility of the monatomic chain (MC) formation for ZnO material was studied by molecular dynamics (MD) simulation. The process of MC formation and the effects of temperature, strain rate and size were studied extensively. The tensile process can be divided to be five stages and the ZnO diatomic chain (DC) can be found. The MD results show that most atoms in MC came from the original surface of ZnO nanowires (NWs). Temperature and strain rate are two important factors affecting the process, and both high temperature and low strain rate in a certain range would be beneficial to the formation of DC. Moreover, the effects of strain rate and temperature could attribute to the Arrhenius model and the energy release mechanism. Furthermore, multi-shell structure was found for the samples under tensile strain and the layer-layer distance was about 3 Å. Our studies based on density functional theory showed that the most stable structure of ZnO DC was confirmed to be linear, and the I-V curve was also got using ATK.
    Keywords: nanowire; diatomic chain; multi-shell structure; ZnO; size effect; temperature and strain rate effects; ATK; Application
    Area: nanowires
    BibTeX: 
    @article{Wang2012a,
  author = {Wang, Bin Bin and Wang, Feng Chao and Zhao, Ya Pu},
  title = {Understanding formation mechanism of ZnO diatomic chain and multi-shell structure using physical mechanics: Molecular dynamics and first-principle simulations},
  journal = {Science China - Physics, Mechanics & Astronomy},
  year = {2012},
  volume = {55},
  number = {6},
  pages = {1138-1146},
  doi = {http://dx.doi.org/10.1007/s11433-012-4760-3}
}
    Chengyong Xu, Guangfu Luo, Qihang Liu, Jiaxin Zheng, Zhimeng Zhang, Shigeru Nagase, Zhengxiang Gao & Jing Lu Giant magnetoresistance in silicene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Nanoscale
    Vol. 4(10), 3111-3117     		 DOI  
    Abstract: By performing first-principle quantum transport calculations, we predict a giant magnetoresistance in zigzag silicene nanoribbons (ZSiNRs) connecting two semi-infinite silicene electrodes through switch of the edge spin direction of ZSiNRs. Spin-filter efficiency of both the antiferromagnetic and ferromagnetic ZSiNRs is sign-changeable with the bias voltage. Therefore, potential application of silicene in spintronics devices is suggested.
    Keywords: ATK; Application; silicene; spin; magnetoresistance;
    Area: graphene; spin
    BibTeX: 
    @article{Xu2012a,
  author = {Xu, Chengyong and Luo, Guangfu and Liu, Qihang and Zheng, Jiaxin and Zhang, Zhimeng and Nagase, Shigeru and Gao, Zhengxiang and Lu, Jing},
  title = {Giant magnetoresistance in silicene nanoribbons},
  journal = {Nanoscale},
  publisher = {The Royal Society of Chemistry},
  year = {2012},
  volume = {4},
  number = {10},
  pages = {3111--3117},
  doi = {http://dx.doi.org/10.1039/C2NR00037G}
}
    Ke Xu, Jing Huang, Zhaoyong Guan, Qunxiang Li & Jinlong Yang Transport spin polarization of magnetic C28 molecular junctions

    [Abstract] [BibTeX]

    		 2012 Chemical Physics Letters
    Vol. 535(0), 111-115     		 DOI URL 
    Abstract: We present a theoretical study of spin transport through a magnetic C28 molecule sandwiched between two Au (111) electrodes. The ab initio modeling is performed by spin density functional theory and nonequilibrium Green's function technique. The results clearly show that the spin-resolved transmission spectra of C28 molecular junctions exhibit robust transport spin polarization (TSP) characteristics, which depends on the contact configuration. At the small bias voltage, the conductance of C28 is mainly determined by the spin-down electrons. The TSP behavior can be effectively tuned by the gate. Our results indicate that C28 molecule holds promise in future molecular spintronics applications.
    Keywords: ATK; Application; fullerene; molecular electronics; spin transport; electron-transport; small fullerenes; spintronics; derivatives; stability; clusters; c28
    Area: fullerenes; spin
    BibTeX: 
    @article{Xu2012b,
  author = {Xu, Ke and Huang, Jing and Guan, Zhaoyong and Li, Qunxiang and Yang, Jinlong},
  title = {Transport spin polarization of magnetic C28 molecular junctions},
  journal = {Chemical Physics Letters},
  year = {2012},
  volume = {535},
  number = {0},
  pages = {111--115},
  url = {http://www.sciencedirect.com/science/article/pii/S0009261412003922},
  doi = {http://dx.doi.org/10.1016/j.cplett.2012.03.066}
}
    C.X. Zhang, Chaoyu He, Zhizhou Yu, L. Xue, K.W. Zhang, L.Z. Sun & Jianxin Zhong Effects of oxygen-containing defect complex on the electronic structures and transport properties of single-walled carbon nanotubes

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(20), 1686-1691     		 DOI URL 
    Abstract: The electronic structures and transport properties of (10,0) single-walled carbon nanotube ((10,0) (SWNT)) with oxygen-containing defect complex are investigated using density functional theory in combination with nonequilibrium Green's function method. The complex delocalizes the local states of (10,0) SWNT induced by mono- and di-vacancy but strengthens the localization of the states induced by the Stone-Wales defect. As a result, the complex partially restores the transport properties of ( 10 , 0 ) SWNT with vacancies, but reduces the transmission of ( 10 , 0 ) SWNT with Stone-Wales defect. However, the oxygen-containing defect complex only slightly influences the transmission gap and threshold voltage of the system.
    Keywords: single-walled carbon nanotube; oxygen-containing defect complex; electronic structure; transport property; vacancies; field-effect transistors; augmented-wave method; adsorption; conductance; states; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Zhang2012,
  author = {Zhang, C.X. and He, Chaoyu and Yu, Zhizhou and Xue, L. and Zhang, K.W. and Sun, L.Z. and Zhong, Jianxin},
  title = {Effects of oxygen-containing defect complex on the electronic structures and transport properties of single-walled carbon nanotubes},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {20},
  pages = {1686--1691},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960112003842},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.03.052}
}
    Genghong Zhang, Xin Luo, Yue Zheng & Biao Wang Giant piezoelectric resistance effect of nanoscale zinc oxide tunnel junctions: first principles simulations

    [Abstract] [BibTeX]

    		 2012 Phys. Chem. Chem. Phys.
    Vol. 14(19), 7051-7058     		 DOI  
    Abstract: Based on first principles simulations and quantum transport calculations, we have investigated in the present work the effect of the mechanical load on transport characteristics and the relative physical properties of nanoscale zinc oxide (ZnO) tunnel junctions, and verified an intrinsic giant piezoelectric resistance (GPR) effect. Our results show that the transport-relevant properties, e.g., the piezoelectric potential (piezopotential), built-in electric field, conduction band offset and electron transmission probability of the junction etc., can obviously be tuned by the applied strain. Accordingly, it is inspiring to find that the current-voltage characteristics and tunneling electro-resistance of the ZnO tunnel junction can significantly be adjusted with the strain. When the applied strain switches from -5% to 5%, an increase of more than 14 times in the tunneling current at a bias voltage of 1.1 V can be obtained. Meanwhile, an increase of up to 2000% of the electro-resistance ratio with respect to the zero strain state can be reached at the same bias voltage and with a 5% compression. According to our investigations, the giant piezoelectric resistance effect of nanoscale ZnO tunnel junctions exhibits great potential in exploiting tunable electronic devices. Furthermore, the methodology of strain engineering revealed in this work may shed light on the mechanical manipulations of electronic devices.
    Keywords: total-energy calculations; field-effect transistor; augmented-wave method; molecular-dynamics; nanowire; nanopiezotronics; piezotronics; interfaces; metals; piezoelectric resistance; tunnel junction; zno; strain effect; ATK; Application
    Area: interfaces
    BibTeX: 
    @article{Zhang2012a,
  author = {Zhang, Genghong and Luo, Xin and Zheng, Yue and Wang, Biao},
  title = {Giant piezoelectric resistance effect of nanoscale zinc oxide tunnel junctions: first principles simulations},
  journal = {Phys. Chem. Chem. Phys.},
  publisher = {The Royal Society of Chemistry},
  year = {2012},
  volume = {14},
  number = {19},
  pages = {7051--7058},
  doi = {http://dx.doi.org/10.1039/C2CP23652D}
}
    P. Zhao, D.S. Liu, Y. Zhang, Y. Su, H.Y. Liu, S.J. Li & G. Chen Large Low Bias Negative Differential Resistance in an Endohedral Li@C60 Dimer Junction

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(14)The Journal of Physical Chemistry C, 7968-7974     		 DOI  
    Abstract: By applying the nonequilibrium Green function formalism combined with density functional theory, we have investigated the electronic transport properties of the C60 dimer and its endohedral complex Li@C60 dimer. Our results show that the doping of Li atoms significantly changes the transport properties of the C60 dimer. Negative differential resistance is found in such systems. Especially, the doping of Li atoms can lead to a much larger negative differential resistance at much lower bias, and it is quite evident from the plot of differential conductance versus bias. The negative differential resistance behavior is understood in terms of the evolution of the transmission spectrum and projected density of states spectrum with applied bias combined with molecular projected self-consistent Hamiltonian states analyses.
    Keywords: ATK; Application; fullerene; transport-properties; molecular junction; carbon nanotube; atoms; temperature; c60; conductance; cluster; device; c-120
    Area: fullerenes
    BibTeX: 
    @article{Zhao2012b,
  author = {Zhao, P. and Liu, D. S. and Zhang, Y. and Su, Y. and Liu, H. Y. and Li, S. J. and Chen, G.},
  title = {Large Low Bias Negative Differential Resistance in an Endohedral Li@C60 Dimer Junction},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {14},
  pages = {7968--7974},
  doi = {http://dx.doi.org/10.1021/jp210880j}
}
    P. Zhao & D.S. Liu First-principle study of the electronic transport properties of a new dumbbell-like carbon nanocomposite

    [Abstract] [BibTeX]

    		 2012 Physica B: Condensed Matter
    Vol. 407(12), 2105-2108     		 DOI URL 
    Abstract: Using a first-principle density functional theory and non-equilibrium Green's function formalism for quantum transport calculation, we have investigated the electronic transport properties of a new dumbbell-like carbon nanocomposite, in which one carbon nanotube segment is capped with two C60 fullerenes. Our results show that the current-voltage curve reveals a highly nonlinear feature. A negative differential resistance (NDR) behavior is obtained at a very low bias, which is expected to be helpful for the development of low bias NDR-based molecular devices. Moreover, the carbon nanotube length and fullerene type can affect the NDR behavior strongly. The electronic transport is analyzed from the transmission spectra and the molecular projected self-consistent Hamiltonian states under different applied biases.
    Keywords: fullerenes; non-equilibrium Green's function; Electronic transport; negative differential resistance; NDR; ATK; Application
    Area: fullerenes
    BibTeX: 
    @article{Zhao2012c,
  author = {Zhao, P. and Liu, D.S.},
  title = {First-principle study of the electronic transport properties of a new dumbbell-like carbon nanocomposite},
  journal = {Physica B: Condensed Matter},
  year = {2012},
  volume = {407},
  number = {12},
  pages = {2105--2108},
  url = {http://www.sciencedirect.com/science/article/pii/S0921452612001913},
  doi = {http://dx.doi.org/10.1016/j.physb.2012.02.015}
}
    P. Zhao, D.S. Liu, Y. Zhang, Y. Su, H.Y. Liu, S.J. Li & G. Chen Electronic transport properties of zigzag carbon- and boron-nitride-nanotube heterostructures

    [Abstract] [BibTeX]

    		 2012 Solid State Communications
    Vol. 152(12), 1061-1066     		 DOI URL 
    Abstract: Using first-principles density functional theory and non-equilibrium Green's function formalism for quantum transport calculation, we have investigated the electronic transport properties of heteronanotubes by joining a zigzag (6,0) carbon nanotube and a zigzag (6,0) boron nitride nanotube with different atomic compositions and joint configurations. Our results show that the atomic composition and joint configuration affect strongly the electronic transport properties. Obvious negative differential resistance behavior and large rectifying behavior are obtained in the heterostructure with certain composition and joint configuration. Moreover, tube length and tube radius can affect strongly the observed NDR and rectifying behaviors. The observed negative differential resistance and rectifying behaviors are explained in terms of the evolution of the transmission spectrum with applied bias combined with molecular projected self-consistent Hamiltonian states analysis.
    Keywords: carbon nanotube; boron nitride nanotube; negative differential resistance; rectifying; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Zhao2012d,
  author = {Zhao, P. and Liu, D.S. and Zhang, Y. and Su, Y. and Liu, H.Y. and Li, S.J. and Chen, G.},
  title = {Electronic transport properties of zigzag carbon- and boron-nitride-nanotube heterostructures},
  journal = {Solid State Communications},
  year = {2012},
  volume = {152},
  number = {12},
  pages = {1061--1066},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109812001561},
  doi = {http://dx.doi.org/10.1016/j.ssc.2012.03.018}
}
    Peng Zhao & De-Sheng Liu Electronic Transport Properties of an Anthraquinone-Based Molecular Switch with Carbon Nanotube Electrodes

    [Abstract] [BibTeX]

    		 2012 Chinese Physics Letters
    Vol. 29(4), 047302-     		 DOI  
    Abstract: Based on the nonequilibrium Green's function method and density functional theory calculations, we theoretically investigate the electronic transport properties of an anthraquinone-based molecular switch with carbon nanotube electrodes. The molecules that comprise the switch can convert between reduced hydroquinone (HQ) and oxidized anthraquinne (AQ) states via redox reactions. Our results show that the on-off ratio is increased one order of magnitude when compared to the case of gold electrodes. Moreover, an obvious negative differential resistance behavior at much low bias (0.07 V) is observed in the HQ form.
    Keywords: ATK; Application; nanotube; switch; negative differential resistance; conductance; devices; nanotube; molecular electronics
    Area: molecular electronics; nanotubes
    BibTeX: 
    @article{Zhao2012e,
  author = {Peng Zhao and De-Sheng Liu},
  title = {Electronic Transport Properties of an Anthraquinone-Based Molecular Switch with Carbon Nanotube Electrodes},
  journal = {Chinese Physics Letters},
  year = {2012},
  volume = {29},
  number = {4},
  pages = {047302--},
  doi = {http://dx.doi.org/10.1088/0256-307X/29/4/047302}
}
    Wen-Kai Zhao, Chuan-Lu Yang, Jing-Fen Zhao, Mei-Shan Wang & Xiao-Guang Ma Orientation effect on the electronic transport properties of C24 fullerene molecule

    [Abstract] [BibTeX]

    		 2012 Physica B: Condensed Matter
    Vol. 407(12), 2247-2253     		 DOI URL 
    Abstract: The transport properties of the cage-like molecule depend on its orientation between the electrodes, but the investigation on the mechanism has not been found. Using first-principle density-functional theory (DFT) and non-equilibrium Green's function (NEGF) formalism for quantum transport calculation, we study the electronic transport properties of C24 fullerene molecule with different orientations in Au-C24-Au two-probe system. The effects of k-point sampling on the Brillouin zone are explored. Our results show that the negative differential resistance of C24 molecule is found in such a system and can be tuned by the molecule's orientation in the two-probe system. We also proposed a mechanism for it. The I-V characteristic under bias voltage is determined. The present findings could be helpful for the application of the C24 molecule in the field of single molecular devices or nanometer electronics.
    Keywords: C24 fullerene; Electronic transport properties; Orientation; First-principle density-functional theory; Non-equilibrium Green's function; Negative differential resistance; ATK; Application
    Area: fullerenes
    BibTeX: 
    @article{Zhao2012f,
  author = {Zhao, Wen-Kai and Yang, Chuan-Lu and Zhao, Jing-Fen and Wang, Mei-Shan and Ma, Xiao-Guang},
  title = {Orientation effect on the electronic transport properties of C24 fullerene molecule},
  journal = {Physica B: Condensed Matter},
  year = {2012},
  volume = {407},
  number = {12},
  pages = {2247--2253},
  url = {http://www.sciencedirect.com/science/article/pii/S0921452612002402},
  doi = {http://dx.doi.org/10.1016/j.physb.2012.03.008}
}
    Benhu Zhou, Benliang Zhou, Aihua Zeng & Guanghui Zhou Electronic transport for pristine and doped crossed graphene nanoribbon junctions with zigzag interfaces

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(20), 1710-1713     		 DOI URL 
    Abstract: Using the fully self-consistent non-equilibrium Green's function (NEGF) method combined with density functional theory, we investigate numerically the electronic transport property for pristine and doped crossed graphene nanoribbon (GNR) junctions. It is demonstrated that in the case of zigzag interfaces, the I-V characteristics of the junction with or without doping always show semiconducting behavior, which is different from that in the case of armchair interfaces [Zhou, Liao, Zhou, Chen, Zhou, Eur. Phys. J. B 76 (2010) 421]. Interestingly, negative differential resistance (NDR) behavior can be clearly observed in a certain bias region for nitrogen-doped shoulder crossed junction. A mechanism for the NDR behavior is suggested.
    Keywords: electronic transport; graphene nanoribbon; NEGF; density functional theory; negative differential resistance; NDR; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Zhou2012,
  author = {Zhou, Benhu and Zhou, Benliang and Zeng, Aihua and Zhou, Guanghui},
  title = {Electronic transport for pristine and doped crossed graphene nanoribbon junctions with zigzag interfaces},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {20},
  pages = {1710--1713},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960112004392},
  doi = {http://dx.doi.org/10.1016/j.physleta.2012.04.012}
}
    Kurt Stokbro, Mads Engelund & Anders Blom Atomic-scale model for the contact resistance of the nickel-graphene interface

    [Abstract] [BibTeX]

    		 2012 Physical Review B
    Vol. 85(16), 165442     		 DOI  
    Abstract: We perform first-principles calculations of electron transport across a nickel-graphene interface. Four different geometries are considered, where the contact area, graphene and nickel surface orientations, and the passivation of the terminating graphene edge are varied. We find covalent bond formation between the graphene layer and the nickel surface, in agreement with other theoretical studies. We calculate the energy-dependent electron transmission for the four systems and find that the systems have very similar edge contact resistance, independent of the contact area between nickel and graphene, and in excellent agreement with recent experimental data. A simple model where graphene is bonded with a metal surface shows that the results are generic for covalently bonded graphene, and the minimum attainable edge contact resistance is twice the ideal edge quantum contact resistance of graphene.
    Keywords: ATK; ATK-SE; Application; graphene; interface; contact resistance; NEGF;
    Area: graphene
    BibTeX: 
    @article{Stokbro2012,
  author = {Stokbro, Kurt and Engelund, Mads and Blom, Anders},
  title = {Atomic-scale model for the contact resistance of the nickel-graphene interface},
  journal = {Physical Review B},
  publisher = {American Physical Society},
  year = {2012},
  volume = {85},
  number = {16},
  pages = {165442},
  doi = {http://dx.doi.org/10.1103/PhysRevB.85.165442}
}
    Yi-Peng An, Wei Ji & Zhong-Qin Yang Z-like Conducting Pathways in Zigzag Graphene Nanoribbons with Edge Protrusions

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(9)The Journal of Physical Chemistry C, 5915-5919     		 DOI  
    Abstract: Electronic transport properties of zigzag graphene nanoribbons (ZGNRs) with one or two triangle protrusions at the edges are studied by using density functional theory combined with nonequilibrium Green's function method. We find the protrusion generally breaks down the edge state along the same edge, which carries the most current in the junction. For the graphene ribbons having even number of zigzag chains, however, the protrusions can increase or decrease significantly the conductance with different relative position of the two protrusions, accompanied by negative differential resistance characteristics. The abnormal increase of the conductance is ascribed to the forming of a new Z-like conducting pathway as well as the ruining of the mirror symmetry of the ribbons. In terms of odd ZGNRs, the introduction of edge protrusions only suppresses current flow and linear I-V curves are achieved. These edge-modified ways make the graphene-based nanomaterials present more abundant electronic transport phenomena and can be useful for the design of future nanoelectronic devices.
    Keywords: graphene; ATK; Application: negative differential resistance; NDR
    Area: graphene
    BibTeX: 
    @article{An2012,
  author = {An, Yi-Peng and Ji, Wei and Yang, Zhong-Qin},
  title = {Z-like Conducting Pathways in Zigzag Graphene Nanoribbons with Edge Protrusions},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {9},
  pages = {5915--5919},
  doi = {http://dx.doi.org/10.1021/jp3003646}
}
    Yi-Peng An & Zhong-Qin Yang Spin-filtering and switching effects of a single-molecule magnet Mn(dmit)[sub 2]

    [Abstract] [BibTeX]

    		 2012 Journal of Applied Physics
    Vol. 111(4), 043713     		 DOI  
    Abstract: We investigated spin-dependent transport properties of a single-molecule magnet Mn(dmit)2 with a coplanar or perpendicular conformation using first-principles density functional theory combined with nonequilibrium Green's function method. It was found that the current flowing through the junction comprised of two Au leads and a Mn(dmit)2 molecule is high spin-polarized, up to a high efficiency of 82%, if the two ligands of the molecule are orientated in the same plane. The current is strongly suppressed when a ligand is rotated and perpendicular to the other. These results suggest that Mn(dmit)2 is a potential candidate for spin filters or molecular switches.
    Keywords: spin polarised transport; molecular electronics; ATK; Application; single-molecule magnet; spin filter; molecular switch
    Area: molecular electronics; spin
    BibTeX: 
    @article{An2012a,
  author = {An, Yi-Peng and Yang, Zhong-Qin},
  title = {Spin-filtering and switching effects of a single-molecule magnet Mn(dmit)[sub 2]},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2012},
  volume = {111},
  number = {4},
  pages = {043713},
  doi = {http://dx.doi.org/10.1063/1.3686722}
}
    Can Cao, Lingna Chen, Weirong Huang & Hui Xu Electronic Transport of Zigzag Graphene Nanoribbons with Edge Hydrogenation and Oxidation

    [Abstract] [BibTeX]

    		 2012 The Open Chemical Physics Journal
    Vol. 4, 1-7     		 DOI  
    Abstract: By using non-equilibrium Green's functions in combination with the density-functional theory, we study the effect of zigzag graphene nanoribbons with edge hydrogenation and oxidation on transport properties. We find that for the ferromagnetic (FM) configuration the ZGNRs with CH2-CH group exhibit spin diode effect in which only one spin can occur under positive bias while the other spin occurs under negative bias. In the antiferromagnetic (AF) state the symmetric ZGNRs with CH2-CH group show the spin filter effect within some specific energy windows. However, the asymmetric ZGNRs with CH2-CH group do not show such a spin filter effect. We also find that the symmetric and asymmetric ZGNRs with C2O-CH group in AF configurations show similar transport behaviors at the Fermi level. Such ZGNRs might be exploited in spintronic nanodevices.
    Keywords: transport properties; spin-diode effect; first-principles; spin filter; ATK; Application; graphene
    Area: graphene; spin
    BibTeX: 
    @article{Cao2012a,
  author = {Can Cao and Lingna Chen and Weirong Huang and Hui Xu},
  title = {Electronic Transport of Zigzag Graphene Nanoribbons with Edge Hydrogenation and Oxidation},
  journal = {The Open Chemical Physics Journal},
  year = {2012},
  volume = {4},
  pages = {1-7},
  doi = {http://dx.doi.org/10.2174/1874412501204010001}
}
    J.C. Dong, H. Li, F.W. Sun & Y.F. Li Importance of Coupling Pattern and Chemical Decoration for Graphene Nanotransistors

    [Abstract] [BibTeX]

    		 2012 J. Phys. Chem. C
    Vol. 116(11)The Journal of Physical Chemistry C, 6762-6769     		 DOI  
    Abstract: The effects of graphene-electrode coupling pattern and chemical decoration of graphene on the electron transport properties of nanoscale graphene field effect transistors (FETs) are systematically investigated. Different from the viewpoint that molecules with thiol ending groups usually connect to Au electrodes through thiolate-gold bonds in molecular devices, the calculated electron transport properties of nanoscale graphene FETs at thiol-gold coupling mode are observed to be well consistent with experimental results. At the thiolate-gold coupling mode nanoscale graphene FETs exhibit pronounced bipolar FET characteristics with on/off ratios up to 320 (n type) and 650 (p type), which are much higher than those of large area graphene FETs. We propose that different coupling patterns between molecules and electrodes are essential factors responsible for the discrepancy between theoretical calculations and experimental studies. Moreover, the performance of nanoscale graphene FETs is observed to be effectively modulated by chemical decoration of graphene. In particular, their on/off ratios can be significantly increased by spacing groups between ending groups and graphene cores. Side substituents of graphene can regulate the performance of these FETs according to their electron-withdrawing ability. Potential implications for the design of high-performance nanoscale graphene FETs can be obtained from these results.
    Keywords: ATK-SE; Application; chemical decoration; field effect transistor;
    Area: graphene
    BibTeX: 
    @article{Dong2012,
  author = {Dong, J. C. and Li, H. and Sun, F. W. and Li, Y. F.},
  title = {Importance of Coupling Pattern and Chemical Decoration for Graphene Nanotransistors},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {J. Phys. Chem. C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {11},
  pages = {6762--6769},
  doi = {http://dx.doi.org/10.1021/jp3005585}
}
    Mohammad Khazaei, Yunye Liang, Natarajan S. Venkataramanan & Yoshiyuki Kawazoe Polymerization of cyanoacetylene under pressure: Formation of carbon nitride polymers and bulk structures

    [Abstract] [BibTeX]

    		 2012 Physical Review B
    Vol. 85(5), 054101-     		 DOI  
    Abstract: High-pressure phase transitions of polar and nonpolar molecular structures of cyanoacetylene (HC3N) are studied by using first-principles simulations at constant pressure. In both polar and nonpolar crystals, at pressure similar to 20 GPa, the cyanoacetylene molecules are interconnected together and form polyacrylonitrile (PA) polymers. At pressure similar to 30 GPa, PA polymers are transformed to polymers with fused pyridine rings (FPR's). The individual geometrical structures of PA and FPR polymers obtained from polar and nonpolar molecular crystals of cyanoacetylene are identical, but their stacking is different. At pressures above 40 GPa, the FPR polymers are interconnected together and new three-dimensional (3D) carbon nitride systems are formed. At ambient pressure, the long-length PA and FPR polymers are metallic, and the created 3D structures are an insulator with energy band gaps around 2.85 eV. The electron transport characteristics of FPR polymers with different lengths are investigated at finite biases by using the nonequilibrium Green's function technique combined with density functional theory (DFT) by connecting the polymers to gold electrodes. The results show that FPR polymers have negative differential resistance behavior. Our time-dependent DFT calculations reveal that FPR polymers can absorb light in the visible region. From our results, it is expected that the FPR polymers will be a good material for optoelectronic applications.
    Keywords: ATK; Application; electronic-structures; conjugated polymer; ab-initio; polyacetylene; polyacenes; phase; crystals; spectra; devices; systems
    Area: molecular electronics
    BibTeX: 
    @article{Khazaei2012,
  author = {Khazaei, Mohammad and Liang, Yunye and Venkataramanan, Natarajan S. and Kawazoe, Yoshiyuki},
  title = {Polymerization of cyanoacetylene under pressure: Formation of carbon nitride polymers and bulk structures},
  journal = {Physical Review B},
  publisher = {American Physical Society},
  year = {2012},
  volume = {85},
  number = {5},
  pages = {054101--},
  doi = {http://dx.doi.org/10.1103/PhysRevB.85.054101}
}
    Manabu Kiguchi, Shigeto Nakashima, Tomofumi Tada, Satoshi Watanabe, Susumu Tsuda, Yasushi Tsuji & Jun Terao Single-Molecule Conductance of pi-Conjugated Rotaxane: New Method for Measuring Stipulated Electric Conductance of pi-Conjugated Molecular Wire Using STM Break Junction

    [Abstract] [BibTeX]

    		 2012 Small
    Vol. 8(5), 726-730     		 DOI  
    Abstract: An electronic conductance with small fluctuations, which is stipulated in single-molecule junctions, is necessary for the precise control of single-molecule devices. However, the suppression of conductance fluctuations in conventional molecular junctions is intrinsically difficult because the fluctuations are related to the contact fluctuations and molecular motion. In the present study involving experimental and theoretical investigations, it is found that covering a single pi-conjugated wire with an alpha-cyclodextrin molecule is a promising technique for suppressing conductance fluctuations. The conductance histogram of the covered molecular junction measured with the scanning tunneling microscope break-junction technique shows that the conductance peak for the covered junction is sharper than that of the uncovered junction. The covering technique thus has two prominent effects: the suppression of intramolecular motion, and the elimination of intermolecular interactions. Theoretical calculations of electronic conductance clearly support these experimental observations.
    Keywords: rotaxane; molecular electronics; nanogap electrodes; pi-conjugated molecules; single-molecule studies; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Kiguchi2012,
  author = {Kiguchi, Manabu and Nakashima, Shigeto and Tada, Tomofumi and Watanabe, Satoshi and Tsuda, Susumu and Tsuji, Yasushi and Terao, Jun},
  title = {Single-Molecule Conductance of pi-Conjugated Rotaxane: New Method for Measuring Stipulated Electric Conductance of pi-Conjugated Molecular Wire Using STM Break Junction},
  journal = {Small},
  publisher = {WILEY-VCH Verlag},
  year = {2012},
  volume = {8},
  number = {5},
  pages = {726--730},
  doi = {http://dx.doi.org/10.1002/smll.201102075}
}
    Kai-Tak Lam & Gengchiau Liang Graphene Nanoelectronics

    [Abstract] [BibTeX]

    		 2012 NanoScience and Technology, 509-527  DOI  
    Abstract: Two-dimensional monolayer graphene has the unique electrical and physical properties which can be exploited in new device structures. However, its application in field-effect device structure is limited due to its semi-metal nature. Therefore, a lot of research efforts have been focussed on introducing an energy bandgap in the electronic structure. For example, a commonly studied method involves cutting two-dimensional graphene into one-dimensional narrow ribbons (graphene nanoribbons), where the spatial quantum confinement introduced by the physical edges generates an energy bandgap that is closely related to the width and edge configurations of the ribbon. Similarly for a bilayer graphene, an energy bandgap can also be obtained like the monolayer graphene nanoribbons, and be further controlled by varying its interlayer distance. In this chapter, a review of the electronic structure of monolayer graphene nanoribbon is presented and the study on the bilayer counterpart is subsequently discussed. Furthermore, based on the electrical properties of the bilayer graphene nanoribbon, the device performance of the Schottky barrier diode is investigated. Lastly, a nanoelectromechanical (NEM) switch based on the floating gate design is presented and discussed.
    Keywords: graphene; nanomechanics; ATK; Application
    Area: graphene
    BibTeX: 
    @inbook{Lam2012,
  author = {Lam, Kai-Tak and Liang, Gengchiau},
  title = {Graphene Nanoelectronics},
  booktitle = {NanoScience and Technology},
  publisher = {Springer Berlin Heidelberg},
  year = {2012},
  pages = {509--527},
  doi = {http://dx.doi.org/10.1007/978-3-642-22984-8_16}
}
    Jinliang Li, Zhenzhen Zhao, Cui Yu, Hongbo Wang & Jianwei Zhao Theoretical investigation on the transportation behavior of molecular wires with redox reaction

    [Abstract] [BibTeX]

    		 2012 Journal of Computational Chemistry
    Vol. 33(6), 666-672     		 DOI  
    Abstract: A series of model molecules [sequential quinone (Q) or hydroquinone (HQ) rings connected by triple bonds] as molecular wires have been investigated by using density functional theory combined with nonequilibrium Green's function method. The results show that the system has two discrete conductance states: a low-conductance state with Q form, and a high-conductance state with HQ form. The systematic investigations have suggested that more Q/HQ pairs in the system may improve the on/off ratio, though long molecule reduces the conductance of the molecular junction. The switch mechanism has been explained via molecular electronic structure as well as transmission spectra.
    Keywords: molecular electronics; molecular wire; transportation; nonequilibrium Green's function; electronic structure; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Li2012a,
  author = {Li, Jinliang and Zhao, Zhenzhen and Yu, Cui and Wang, Hongbo and Zhao, Jianwei},
  title = {Theoretical investigation on the transportation behavior of molecular wires with redox reaction},
  journal = {Journal of Computational Chemistry},
  publisher = {Wiley Subscription Services, Inc., A Wiley Company},
  year = {2012},
  volume = {33},
  number = {6},
  pages = {666--672},
  doi = {http://dx.doi.org/10.1002/jcc.22895}
}
    Xiao-Fei Li, Ling-Ling Wang, Ke-Qiu Chen & Yi Luo Electronic transport through zigzag/armchair graphene nanoribbon heterojunctions

    [Abstract] [BibTeX]

    		 2012 Journal of Physics: Condensed Matter
    Vol. 24(9), 095801     		 DOI URL 
    Abstract: The electronic transport properties of a graphene nanoribbon (GNR) are known to be sensitive to its width, edges and defects. We investigate the electronic transport properties of a graphene nanoribbon heterojunction constructed by fusing a zigzag and an armchair graphene nanoribbon (zGNR/aGNR) side by side. First principles results reveal that the heterojunction can be either metallic or semiconducting, depending on the width of the nanoribbons. Intrinsic rectification behaviors have been observed, which are largely sensitive to the connection length between the zGNR and aGNR. The microscopic origins of the rectification behavior have been revealed. We find that the carrier type can alter from electrons to holes with the bias voltage changing from negative to positive; the asymmetrical transmission spectra of electrons and holes induced by the interface defects directly results in the rectification behavior. The results suggest that any methods which can enhance the asymmetry of the transmission spectra between holes and electrons could be used to improve the rectification behavior in the zGNR/aGNR heterojunction. Our findings could be useful for designing graphene based electronic devices.
    Keywords: graphene heterojunction; nanoribbon; rectification; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Li2012c,
  author = {Xiao-Fei Li and Ling-Ling Wang and Ke-Qiu Chen and Yi Luo},
  title = {Electronic transport through zigzag/armchair graphene nanoribbon heterojunctions},
  journal = {Journal of Physics: Condensed Matter},
  year = {2012},
  volume = {24},
  number = {9},
  pages = {095801},
  url = {http://stacks.iop.org/0953-8984/24/i=9/a=095801},
  doi = {http://dx.doi.org/10.1088/0953-8984/24/9/095801}
}
    Ana Martín-Lasanta, Delia Miguel, Trinidad García, Juan A. López-Villanueva, Salvador Rodríguez-Bolívar, Francisco M. Gómez-Campos, Elena Buñuel, Diego J. Cárdenas, Luis Álvarez de Cienfuegos & Juan M. Cuerva Influence of the Number of Anchoring Groups on the Electronic and Mechanical Properties of Benzene-, Anthracene- and Pentacene-Based Molecular Devices

    [Abstract] [BibTeX]

    		 2012 ChemPhysChem
    Vol. 13(3), 860-868     		 DOI  
    Abstract: One of the central issues of molecular electronics (ME) is the study of the molecule-metal electrode contacts, and their implications for the conductivity, charge-transport mechanism, and mechanical stability. In fact, stochastic on/off switching (blinking) reported in STM experiments is a major problem of single-molecule devices, and challenges the stability and reliability of these systems. Surprisingly, the ambiguous STM results all originate from devices that bind to the metallic electrode through a one-atom connection. In the present work, DFT is employed to study and compare the properties of a set of simple acenes that bind to metallic electrodes with an increasing number of connections, in order to determine whether the increasing numbers of anchoring groups have a direct repercussion on the stability of these systems. The conductivities of the three polycyclic aromatic hydrocarbons are calculated, as well as their transmission spectra and current profiles. The thermal and mechanical stability of these systems is studied by pulling and pushing the metal-molecule connection. The results show that molecules with more than one connection per electrode exhibit greater electrical efficiency and current stability.
    Keywords: density-functional theory; au(111) surface; orbital views; conductance; junctions; gold; transport; stability; fabrication; geometry; acenes; density functional calculations; electron transport; molecular dynamics; nanotechnology; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Martin-Lasanta2012,
  author = {Ana Martín-Lasanta and Delia Miguel and Trinidad García and Juan A. López-Villanueva and Salvador Rodríguez-Bolívar and Francisco M. Gómez-Campos and Elena Buñuel and Diego J. Cárdenas and Luis Álvarez de Cienfuegos and Juan M. Cuerva},
  title = {Influence of the Number of Anchoring Groups on the Electronic and Mechanical Properties of Benzene-, Anthracene- and Pentacene-Based Molecular Devices},
  journal = {ChemPhysChem},
  publisher = {WILEY-VCH Verlag},
  year = {2012},
  volume = {13},
  number = {3},
  pages = {860--868},
  doi = {http://dx.doi.org/10.1002/cphc.201100582}
}
    Vitesh Mistry, Vihar P. Georgiev & John E. McGrady Electron transport through molecular wires based on a face-shared bioctahedral motif

    [Abstract] [BibTeX]

    		 2012 Comptes Rendus Chimie
    Vol. 15(2-3)Polyoxometalates, metal wires and other polymetallic complexes: structure, properties, theoretical modelling. A tribute to Marie-Madeleine Rohmer, 176-183     		 DOI URL 
    Abstract: Density functional theory in conjunction with non-equilibrium Green's functions is used to explore the electron transport properties of a series of molecules based on the face-shared bioctahedral (M2Cl9) motif. The metal-metal bond orders in the chosen molecules, [Rh2Cl9]3-, [Ru2Cl9]3- and [Mo2Cl9]3- vary from 0 (Rh) to 1 (Ru) and 3 (Mo), and the calculations indicate that there is a direct correlation between conductance and bond order. The [Mo2Cl9]3- case is particularly interesting as it is well known from crystallographic studies to be very flexible, the Mo-Mo bond length varying over a range of ~0.35 Å depending on cation. The upper limit of this range marks the point where homolytic cleavage of the sigma-pi components of the triple bond is complete, and this has a marked impact on electron transport. The localization of the metal-based orbitals means that those on the left (source) and right (drain) sides respond very differently to applied bias, giving rise to resonance effects at particular bias voltages, and hence to negative differential resistance effects.
    Keywords: density functional theory; electron transport; metal-metal bonds; ATK; Application; molecular magnet; negative differential resistance; metal-atom chains; ab-initio; carbon nanotubes; spin transport; cyclopentadienyl; conductance; benzene; complexes; junctions
    Area: molecular electronics; spin
    BibTeX: 
    @article{Mistry2012,
  author = {Mistry, Vitesh and Georgiev, Vihar P. and McGrady, John E.},
  title = {Electron transport through molecular wires based on a face-shared bioctahedral motif},
  booktitle = {Polyoxometalates, metal wires and other polymetallic complexes: structure, properties, theoretical modelling. A tribute to Marie-Madeleine Rohmer},
  journal = {Comptes Rendus Chimie},
  year = {2012},
  volume = {15},
  number = {2-3},
  pages = {176--183},
  url = {http://www.sciencedirect.com/science/article/pii/S1631074811002232},
  doi = {http://dx.doi.org/10.1016/j.crci.2011.11.001}
}
    Ruge Quhe, Jiaxin Zheng, Guangfu Luo, Qihang Liu, Rui Qin, Jing Zhou, Dapeng Yu, Shigeru Nagase, Wai-Ning Mei, Zhengxiang Gao & Jing Lu Tunable and sizable band gap of single-layer graphene sandwiched between hexagonal boron nitride

    [Abstract] [BibTeX]

    		 2012 NPG Asia Materials
    Vol. 4, e6     		 DOI  
    Abstract: Opening a tunable and sizable band gap in single-layer graphene (SLG) without degrading its structural integrity and carrier mobility is a significant challenge. Using density functional theory calculations, we show that the band gap of SLG can be opened to 0.16 eV (without an electric field) and 0.34 eV (with a strong electric field) when properly sandwiched between two hexagonal boron nitride single layers. The zero-field band gaps are increased by more than 50% when the many-body effects are included. The ab initio quantum transport simulation of a dual-gated field effect transistor (FET) made of such a sandwich structure reveals an electric-field-enhanced transport gap, and the on/off current ratio is increased by a factor of 8.0 compared with that of a pure SLG FET. The tunable and sizeable band gap and structural integrity render this sandwich structure a promising candidate for high-performance SLG FETs.
    Keywords: ATK; Application; density functional theory; electric field; graphene; h-BN sheet; quasiparticle correction; transport properties; field-effect transistor
    Area: graphene
    BibTeX: 
    @article{Quhe2012,
  author = {Quhe, Ruge and Zheng, Jiaxin and Luo, Guangfu and Liu, Qihang and Qin, Rui and Zhou, Jing and Yu, Dapeng and Nagase, Shigeru and Mei, Wai-Ning and Gao, Zhengxiang and Lu, Jing},
  title = {Tunable and sizable band gap of single-layer graphene sandwiched between hexagonal boron nitride},
  journal = {NPG Asia Materials},
  publisher = {Nature Japan KK},
  year = {2012},
  volume = {4},
  pages = {e6},
  doi = {http://dx.doi.org/10.1038/am.2012.10}
}
    Cai-Juan Xia, De-Sheng Liu, Han-Chen Liu & Ying-Tang Zhang Effect of Chemical Modifications on the Electronic Transport Properties of the Optical Molecular Switch

    [Abstract] [BibTeX]

    		 2012 Japanese Journal of Applied Physics
    Vol. 51(1), 011601     		 DOI  
    Abstract: Using first-principles density functional theory and nonequilibrium Green's function formalism, we investigate the effect of chemical modifications on the electronic transport properties of the dihydroazulene optical molecular switch. The molecule that comprises the switch can convert between the closed and the open forms upon photoexcitation. Theoretical results show that the chemical modifications play an important role in determining the switching behavior of such molecular device. This result reflects that the current ratio can be manipulated with the careful selection of the substituents and can provide fundamental guidelines for the design of functional molecular devices.
    Keywords: optical molecular switch; conductance; resistance; surface; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Xia2012,
  author = {Cai-Juan Xia and De-Sheng Liu and Han-Chen Liu and Ying-Tang Zhang},
  title = {Effect of Chemical Modifications on the Electronic Transport Properties of the Optical Molecular Switch},
  journal = {Japanese Journal of Applied Physics},
  year = {2012},
  volume = {51},
  number = {1},
  pages = {011601},
  doi = {http://dx.doi.org/10.1143/JJAP.51.011601}
}
    Peng Zhao, DeSheng Liu & Wei Liang Effects of tip separation and orientation on negative differential resistance in boron-doped carbon-nanotube-based molecular junctions

    [Abstract] [BibTeX]

    		 2012 Chinese Science Bulletin
    Vol. 57(9), 966-969     		 DOI  
    Abstract: We investigate using the Landauer formalism, which combines both the non-equilibrium Green's function and density functional theory, the effects of separation and orientation between two electrodes of boron-doped capped-carbon-nanotube-based molecular junctions on negative differential resistance. The results show that this negative differential resistance behavior is strongly dependent on the separation and orientation between the two electrodes. A gap width of 0.35 nm and maximal symmetry achieves the best negative differential resistance behavior.
    Keywords: ATK; Application; doping; negative differential resistance; molecular junction; carbon nanotube; non-equilibrium Green's function; density functional theory
    Area: nanotubes
    BibTeX: 
    @article{Zhao2012a,
  author = {Zhao, Peng and Liu, DeSheng and Liang, Wei},
  title = {Effects of tip separation and orientation on negative differential resistance in boron-doped carbon-nanotube-based molecular junctions},
  journal = {Chinese Science Bulletin},
  year = {2012},
  volume = {57},
  number = {9},
  pages = {966-969},
  doi = {http://dx.doi.org/10.1007/s11434-012-4972-y}
}
    H. Zheng, H.J. Liu, X.J. Tan, H.Y. Lv, L. Pan, J. Shi & X.F. Tang Enhanced thermoelectric performance of graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(9), 093104     		 DOI  
    Abstract: The thermoelectric properties of a series of armchair and zigzag graphene nanoribbons with narrow width are examined using nonequilibrium Green function method and molecular dynamics simulations. It is found that these nanoribbons are rather stable when the edge atoms are passivated by hydrogen and those with armchair edges exhibit much better thermoelectric performance than their zigzag counterparts. Moreover, the corresponding ZT value increases with decreasing ribbon width. By optimizing the doping level, a room temperature ZT of 6.0 can be achieved for the narrowest armchair nanoribbon. The significantly enhanced ZT value makes armchair graphene nanoribbon a promising candidate for thermoelectric applications.
    Keywords: thermoelectricity; graphene; ATK; Application
    Area: graphene; thermo
    BibTeX: 
    @article{Zheng2012,
  author = {Zheng, H. and Liu, H. J. and Tan, X. J. and Lv, H. Y. and Pan, L. and Shi, J. and Tang, X. F.},
  title = {Enhanced thermoelectric performance of graphene nanoribbons},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {9},
  pages = {093104},
  doi = {http://dx.doi.org/10.1063/1.3689780}
}
    L. Zhu, K.L. Yao & Z.L. Liu Biradical and triradical organic magnetic molecules as spin filters and rectifiers

    [Abstract] [BibTeX]

    		 2012 Chemical Physics
    Vol. 397(0), 1 - 8     		 DOI  
    Abstract: We have theoretically investigated the spin-polarized transport properties of molecular junctions consisting of biradical and triradical organic magnetic molecules sandwiched between two symmetric gold electrodes, respectively. It shows that these junctions function as a spin rectifier or a combination of spin and charge rectifiers with high spin rectification ratios exceeding 100, wherein the spin diode/rectification effect stems from the conjugated length and asymmetry of the molecular framework, which is the pre-requisite for electronic asymmetry of the adsorbed species. The negative differential resistance, spin-filtering and switching properties are also unveiled. In particular, it is revealed that the strong couplings between the electrodes and molecules are responsible for the negative differential resistance.
    Keywords: spin transport; organic spin rectifier; negative differential resistance; spin filtering; molecular electronics; hexadecylquinolinium tricyanoquinodimethanide; electrical rectification; transport-properties; conductance; nitroxide; monolayer; exchange; junction; ATK; Application
    Area: molecular electronics; spin
    BibTeX: 
    @article{Zhu2012,
  author = {L. Zhu and K.L. Yao and Z.L. Liu},
  title = {Biradical and triradical organic magnetic molecules as spin filters and rectifiers},
  journal = {Chemical Physics},
  year = {2012},
  volume = {397},
  number = {0},
  pages = {1 - 8},
  doi = {http://dx.doi.org/10.1016/j.chemphys.2011.09.009}
}
    Wei Zou, Zhizhou Yu, C.X. Zhang, J.X. Zhong & L.Z. Sun Transport properties of hybrid graphene/graphane nanoribbons

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(10), 103109     		 DOI  
    Abstract: The transport properties of hybrid nanoribbons constructed by substituting zigzag graphane nanoribbons into zigzag graphene nanoribbons are investigated using the first-principles calculations and non-equilibrium Green's function. The transport properties of the hybrid systems are improved due to the appearance of transport platform with nontrivial conductance around the Fermi level. This enhancement attributes to the extra bands induced by the substituted graphane nanoribbons. Moreover, this enhancement is sensitive to the position and concentration of the substituted graphane nanoribbons in the system. Our results indicate that such hybrid system is an effective approach to modulate the transport properties of zigzag graphene nanoribbons.
    Keywords: wide band gap semiconductors; graphene; graphane; nanoribbons; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Zou2012,
  author = {Zou, Wei and Yu, Zhizhou and Zhang, C. X. and Zhong, J. X. and Sun, L. Z.},
  title = {Transport properties of hybrid graphene/graphane nanoribbons},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {10},
  pages = {103109},
  doi = {http://dx.doi.org/10.1063/1.3692725}
}
    Jing Huang, Ke Xu, Shulai Lei, Haibin Su, Shangfeng Yang, Qunxiang Li & Jinlong Yang Iron-phthalocyanine molecular junction with high spin filter efficiency and negative differential resistance

    [Abstract] [BibTeX]

    		 2012 The Journal of Chemical Physics
    Vol. 136(6), 064707     		 DOI  
    Abstract: We investigate the spin transport properties of iron-phthalocyanine (FePc) molecule sandwiched between two N-doped graphene nanoribbons (GNRs) based on the density functional theory and nonequilibrium Green's function methods. Our calculated results clearly reveal that the FePc molecular junction has high spin-filter efficiency as well as negative differential resistance (NDR). The zero-bias conductance through FePc molecule is dominated by the spin-down electrons, and the observed NDR originates from the bias-dependent effective coupling between the FePc molecular orbitals and the narrow density of states of electrodes. The remarkable high spin-filter efficiency and NDR are robust regardless of the edge shape and the width of GNRs, and the N-doping site in GNRs. These predictions indicate that FePc junction holds great promise in molecular electronics and spintronics applications.
    Keywords: density functional theory; electrodes; electronic density of states; graphene; Green's function methods; iron compounds; nanoribbons; negative resistance; nitrogen; orbital calculations; organic compounds; spin polarised transport; graphene; molecular electronics; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Huang2012,
  author = {Huang, Jing and Xu, Ke and Lei, Shulai and Su, Haibin and Yang, Shangfeng and Li, Qunxiang and Yang, Jinlong},
  title = {Iron-phthalocyanine molecular junction with high spin filter efficiency and negative differential resistance},
  journal = {The Journal of Chemical Physics},
  publisher = {AIP},
  year = {2012},
  volume = {136},
  number = {6},
  pages = {064707},
  doi = {http://dx.doi.org/10.1063/1.3684551}
}
    X.Q. Deng, Z.H. Zhang, G.P. Tang, Z.Q. Fan, M. Qiu & C. Guo Rectifying behaviors induced by BN-doping in trigonal graphene with zigzag edges

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(6), 063107     		 DOI  
    Abstract: Based on nonequilibrium Green's functions in combination with density-function theory, the transport properties of trigonal graphenes, with the vertex carbon atom substituted by one phosphorus or boron atom and bounded through a B-N pair, coupled to gold electrodes are investigated. The rectification behavior can be observed because a potential barrier similar to the p-n junction is formed in the B-N region of central molecule. When the size of a central molecule is enlarged, rectification ratio is improved greatly since the barrier height in it is enhanced as well.
    Keywords: rectification; density functional theory; doping; graphene; Green's function methods; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Deng2012,
  author = {Deng, X. Q. and Zhang, Z. H. and Tang, G. P. and Fan, Z. Q. and Qiu, M. and Guo, C.},
  title = {Rectifying behaviors induced by BN-doping in trigonal graphene with zigzag edges},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {6},
  pages = {063107},
  doi = {http://dx.doi.org/10.1063/1.3681779}
}
    Hua Hao, XiaoHong Zheng, RuiNing Wang, Zhi Zeng & H.Q. Lin Spin-flip effect on transport properties of a Mn[sub 3] molecule

    [Abstract] [BibTeX]

    		 2012 Journal of Applied Physics
    Vol. 111(7), 07B303     		 DOI  
    Abstract: Electron transport through a single-molecule magnet [NEt4](3)[Mn3Zn2(salox)(3)O(N-3)(6)Cl-2] is investigated by spin-polarized density functional theory combined with the Keldysh nonequilibrium Green's function technique. Our study demonstrates that spin-filtering effect and negative differential resistance exist in the ground state of this molecule. When the magnetic state of the molecule is changed from its ground state to the spin-flip state, substantial changes are induced not only in energy levels of the molecule, but also in the coupling of molecular states with eigenstates of Ag(100) nano-electrodes, which lead to the disappearance of spin-filtering effect and negative differential resistance.
    Keywords: density functional theory; eigenvalues and eigenfunctions; electrodes; Green's function methods; ground states; manganese; molecular electronic states; spin polarised transport; ATK; Application; magnets
    Area: molecular electronics; spin
    BibTeX: 
    @article{Hao2012a,
  author = {Hao, Hua and Zheng, XiaoHong and Wang, RuiNing and Zeng, Zhi and Lin, H. Q.},
  title = {Spin-flip effect on transport properties of a Mn[sub 3] molecule},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2012},
  volume = {111},
  number = {7},
  pages = {07B303},
  doi = {http://dx.doi.org/10.1063/1.3670984}
}
    En Ling Li, Peng Fei Zhu, Tao Zhao, De Ming Ma & Xue Wen Wang Study of Electronic Structures and Transport Properties on Saturated GaN Nanowires

    [Abstract] [BibTeX]

    		 2012 Advanced Materials Research
    Vol. 465, 118-124     		 DOI  
    Abstract: Geometry structure, electronic structure and electronic transport properties of saturated hexagonal single crystalline GaN nanowires in the [001] growth direction have been investigated based on generalized gradient approximation (GGA) of density functional theory (DFT) and non-equilibrium Green's function (NEGF) method. The results show, there is a contraction of the bond lengths of the saturated GaN nanowires after optimization; the nanowires have direct band gap, and band gap decreases with the increase of the cross section of nanowires; the electronic density of state and electronic transmission spectra of two-probe system have their own pulse-type sharp peaks with almost the same location of electron energy; the curves of I-V characteristics of the three saturated GaN nanowires are symmetric over the entire bias-voltage range, and they are semiconducting.
    Keywords: ATK; Application; density functional theory (DFT); electronic transport; GaN nanowires
    Area: nanowires
    BibTeX: 
    @article{Li2012b,
  author = {En Ling Li and Peng Fei Zhu and Tao Zhao and De Ming Ma and Xue Wen Wang},
  title = {Study of Electronic Structures and Transport Properties on Saturated GaN Nanowires},
  journal = {Advanced Materials Research},
  year = {2012},
  volume = {465},
  pages = {118-124},
  doi = {http://dx.doi.org/10.4028/www.scientific.net/AMR.465.118}
}
    Chen Ming, Zheng-Zhe Lin, Jun Zhuang & Xi-Jing Ning Electronic rectification devices from carbon nanocones

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(6), 063119     		 DOI  
    Abstract: The electronic rectification effects of single wall carbon nanocones (SWCNCs) with cone angles 113°, 60°, and 39° are shown by density functional theory calculation and non-equilibrium Green's functional method, and the 113° cone owns the best rectification. Based on this result, the experiment on the rectification effects of cone-like structures is explained. To realize the rectification device, a scheme for fabricating single wall carbon nanocones standing on substrates with the controlled cone shapes is suggested and was verified via molecular dynamics simulations.
    Keywords: carbon; density functional theory; Green's function methods; molecular dynamics method; molecular electronics; nanoelectronics; nanofabrication; nanostructured materials; rectification; rectifiers; ATK; Application
    Area: nanotubes; graphene
    BibTeX: 
    @article{Ming2012,
  author = {Ming, Chen and Lin, Zheng-Zhe and Zhuang, Jun and Ning, Xi-Jing},
  title = {Electronic rectification devices from carbon nanocones},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {6},
  pages = {063119},
  doi = {http://dx.doi.org/10.1063/1.3684276}
}
    Lei Shen, Tiejun Zhou, Zhaoqiang Bai, Minggang Zeng, Jing Qiang Goh, Zhi min Yuan, Guchang Han, Bo Liu & Yuan Ping Feng Systematic study of ferroelectric, interfacial, oxidative, and doping effects on conductance of Pt/BaTiO_3/Pt ferroelectic tunnel junctions

    [Abstract] [BibTeX]

    		 2012 Physical Review B
    Vol. 85(6), 064105     		 DOI  
    Abstract: Using the nonequilibrium Green's function method combined with density functional theory, we systematically study the ferroelectric, interfacial, oxidative, and doping effects on electron transport of BaTiO3-based ferroelectric tunnel junctions (Pt/BaTiO3/Pt). The ferroelectric effect reduces the tunneling conductance compared to nonferroelectric BaTiO3 due to the large decay rate of the Delta5 (py and dyz) band. The TiO2-terminated interface shows a better tunneling conductance than the BaO-terminated interface since electrons mainly transport through the Ti3d-Op bonding state. Interfacial oxidation strongly reduces the conductance due to trapping of electrons and interfacial charge localization by additional O ions, while Nb doping enhances the conductance due to the delocalized distribution of charges on orbitals of the transport channel. Our studies provide a useful guide to practical applications of tunnel junctions with ferroelectric barriers.
    Keywords: ATK; Application; interfaces; spin; ferroelectricity; MTJ;
    Area: interfaces; spin; semi; nvm
    BibTeX: 
    @article{Shen2012,
  author = {Shen, Lei and Zhou, Tiejun and Bai, Zhaoqiang and Zeng, Minggang and Goh, Jing Qiang and Yuan, Zhi-min and Han, Guchang and Liu, Bo and Feng, Yuan Ping},
  title = {Systematic study of ferroelectric, interfacial, oxidative, and doping effects on conductance of Pt/BaTiO_3/Pt ferroelectic tunnel junctions},
  journal = {Physical Review B},
  publisher = {American Physical Society},
  year = {2012},
  volume = {85},
  number = {6},
  pages = {064105},
  doi = {http://dx.doi.org/10.1103/PhysRevB.85.064105}
}
    Ting-Ting Wu, Xue-Feng Wang, Ming-Xing Zhai, Hua Liu, Liping Zhou & Yong-Jin Jiang Negative differential spin conductance in doped zigzag graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(5), 052112     		 DOI  
    Abstract: The spin dependent charge transport in zigzag graphene nanoribbons (ZGNRs) has been investigated by the nonequilibrium Green's function method combined with the density functional theory at the local spin density approximation. The current versus voltage curve shows distinguished behaviors for symmetric and asymmetric ZGNRs, and the doping on the ZGNR edges can manipulate the spin transport. In special cases that a Be atom is substitutionally doped on one edge of the symmetric ZGNRs, one spin current shows negative differential resistance, whereas the other increases monotonically with the bias. This property might be used to design spin oscillators or other devices for spintronics.
    Keywords: beryllium; density functional theory; graphene; Green's function methods; nanoribbons; negative resistance; spin polarised transport; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Wu2012a,
  author = {Ting-Ting Wu and Xue-Feng Wang and Ming-Xing Zhai and Hua Liu and Liping Zhou and Yong-Jin Jiang},
  title = {Negative differential spin conductance in doped zigzag graphene nanoribbons},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {5},
  pages = {052112},
  doi = {http://dx.doi.org/10.1063/1.3681775}
}
    R. Chowdhury, S. Adhikari & P. Rees Graphene based single molecule nanojunction

    [Abstract] [BibTeX]

    		 2012 Physica B: Condensed Matter
    Vol. 407(5), 855-858     		 DOI  
    Abstract: We introduce the ab-initio framework for zigzag-edged graphene fragment based single-electron transistor (SET) operating in the Coulomb blockade regime. Graphene is modeled using the density-functional theory and the environment is described by a continuum model. The interaction between graphene and the SET environment is treated self-consistently through the Poisson equation. We calculate the charging energy as a function of an external gate potential, and from this we obtain the charge stability diagram. Specifically, the importance of including re-normalization of the charge states due to the polarization of the environment has been demonstrated.
    Keywords: Graphene fragment; Ab-initio; Single-electron transistor; Coulomb blockade; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Chowdhury2012,
  author = {Chowdhury, R. and Adhikari, S. and Rees, P.},
  title = {Graphene based single molecule nanojunction},
  journal = {Physica B: Condensed Matter},
  year = {2012},
  volume = {407},
  number = {5},
  pages = {855--858},
  doi = {http://dx.doi.org/10.1016/j.physb.2011.12.101}
}
    Hua Hao, XiaoHong Zheng, LingLing Song, RuiNing Wang & Zhi Zeng Electrostatic Spin Crossover in a Molecular Junction of a Single-Molecule Magnet Fe_2

    [Abstract] [BibTeX]

    		 2012 Physical Review Letters
    Vol. 108(1), 017202-     		 DOI  
    Abstract: Spin crossover by means of an electric bias is investigated by spin-polarized density-functional theory calculations combined with the Keldysh nonequilibrium Green's technique in a molecular junction, where an individual single-molecule magnet Fe2(acpybutO)(O2CMe)(NCS)2 is sandwiched between two infinite Au(100) nanoelectrodes. Our study demonstrates that the spin crossover, based on the Stark effect, is achieved in this molecular junction under an electric bias but not in the isolated molecule under external electric fields. The main reason is that the polarizability of the molecular junction has an opposite sign to that of the isolated molecule, and thus from the Stark effect the condition for the spin crossover in the molecular junction is contrary to that in the isolated molecule.
    Keywords: ATK; Application; spin; molecular magnet; molecular junction; Stark effect;
    Area: molecular electronics; spin
    BibTeX: 
    @article{Hao2012,
  author = {Hao, Hua and Zheng, XiaoHong and Song, LingLing and Wang, RuiNing and Zeng, Zhi},
  title = {Electrostatic Spin Crossover in a Molecular Junction of a Single-Molecule Magnet Fe_2},
  journal = {Physical Review Letters},
  publisher = {American Physical Society},
  year = {2012},
  volume = {108},
  number = {1},
  pages = {017202--},
  doi = {http://dx.doi.org/10.1103/PhysRevLett.108.017202}
}
    Jun He & Ke-Qiu Chen Humidity effects on the electronic transport properties in carbon based nanoscale device

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(6-7), 869-874     		 URL 
    Abstract: By applying nonequilibrium Green's functions in combination with the density functional theory, we investigate the effect of humidity on the electronic transport properties in carbon based nanoscale device. The results show that different humidity may form varied localized potential barrier, which is a very important factor to affect the stability of electronic transport in the nanoscale system. A mechanism for the humidity effect is suggested.
    Keywords: humidity effect; fullerenes and related materials; electronic transport; first-principles; nanotube; ATK; Application
    Area: nanotubes; fullerenes
    BibTeX: 
    @article{He2012,
  author = {He, Jun and Chen, Ke-Qiu},
  title = {Humidity effects on the electronic transport properties in carbon based nanoscale device},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {6-7},
  pages = {869--874},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960112000515}
}
    Guomin Ji, Dongmei Li, Changfeng Fang, Yuqing Xu, Yaxin Zhai, Bin Cui & Desheng Liu Effect of contact interface configuration on electronic transport in (C20)2-based molecular junctions

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(5), 773-778     		 DOI  
    Abstract: Using first-principles calculations, we study the electronic transport properties in Au(C20)2Au molecular junctions with different contact interface configurations: point contact and bond contact. We observe that the transmission through the bond contact is considerably higher than that of point contact. Furthermore, the I-V characteristics are rather different. For the bond contact, we get a metallic behavior followed by a varistor-type behavior. While as for the point contact, the current increases very slowly in a nonlinear way and is one order of magnitude smaller than that of bond contact. We attribute these obvious differences to the distinct contact configurations.
    Keywords: Molecular electronics; First-principles; Electron transport; C20; fullerene; ATK; Application
    Area: fullerenes; molecular electronics
    BibTeX: 
    @article{Ji2012,
  author = {Ji, Guomin and Li, Dongmei and Fang, Changfeng and Xu, Yuqing and Zhai, Yaxin and Cui, Bin and Liu, Desheng},
  title = {Effect of contact interface configuration on electronic transport in (C20)2-based molecular junctions},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {5},
  pages = {773--778},
  doi = {http://dx.doi.org/10.1016/j.physleta.2011.12.025}
}
    Jianming Jia, Shin-Pon Ju, Daning Shi & Kuan-Fu Lin Electrical transport through heterojunctions of single-walled carbon/silicon carbide/carbon nanotubes

    [Abstract] [BibTeX]

    		 2012 Journal of Applied Physics
    Vol. 111(1), 013704     		 DOI  
    Abstract: The transport properties of heterojunctions composed of SiC nanotubes (SiCNTs) with different length coupled between metallic carbon nanotubes (CNTs) have been investigated using a combined density-functional theory and nonequilibrium Green's function formalism. It is shown that the conductance of heterojunction decreases exponentially with the increasing length of SiCNT. The current-voltage curve of the system is linear for short SiCNT, but becomes gradually nonlinear for longer SiCNT, indicating a transition from metallic characteristics to semiconductor-like behavior. The observed trends can be understood by the electron tunneling between metallic CNTs. The present results provide insights into the physical mechanism of heterojunctions and are useful for their applications in electronic devices.
    Keywords: carbon nanotubes; density functional theory; Green's function methods; semiconductor heterojunctions; silicon compounds; tunnelling; wide band gap semiconductors; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Jia2012,
  author = {Jianming Jia and Shin-Pon Ju and Daning Shi and Kuan-Fu Lin},
  title = {Electrical transport through heterojunctions of single-walled carbon/silicon carbide/carbon nanotubes},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2012},
  volume = {111},
  number = {1},
  pages = {013704},
  doi = {http://dx.doi.org/10.1063/1.3673793}
}
    Yong-Jun Li, Ming-Da Li, Jian-Shuang Liu, Qing-Qing Sun, Peng Zhou, Peng-Fei Wang, Shi-Jin Ding & David Wei Zhang Atomic scale investigation of the abnormal transport properties in bilayer graphene nanoribbon

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(1), 013110-3     		 DOI  
    Abstract: We investigate the transport properties of bilayer AA-stacking zigzag graphene nanoribbons (bi-zGNRs) and observe abnormal I-V characteristics which are sensitive to the number of carbon chains across the ribbons. Combining the chirality selective rule of Dirac electrons in graphene and the symmetry of eigenstates, we attribute the abnormal current behavior to the chirality mismatch of energy states. The mismatch causes the suppression of transmission pathways between two electrodes which lead to saturated current with increasing bias for certain ribbons.
    Keywords: carrier mobility; chirality; eigenvalues and eigenfunctions; energy states; bilayer graphene nanoribbon; nanostructured materials; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Li2012,
  author = {Li, Yong-Jun and Li, Ming-Da and Liu, Jian-Shuang and Sun, Qing-Qing and Zhou, Peng and Wang, Peng-Fei and Ding, Shi-Jin and Zhang, David Wei},
  title = {Atomic scale investigation of the abnormal transport properties in bilayer graphene nanoribbon},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {1},
  pages = {013110--3},
  doi = {http://dx.doi.org/10.1063/1.3673324}
}
    Z.Z. Lin, J. Zhuang & X.J. Ning High-efficient tunable infrared laser from monatomic carbon chains

    [Abstract] [BibTeX]

    		 2012 EPL (Europhysics Letters)
    Vol. 97(2), 27006     		 DOI  
    Abstract: Based on ab initio calculations, short B-doped monatomic carbon chains (MCCs) are suggested to serve as working medium for tunable infrared lasers. The MCCs derived from single-layer graphene in vacuum are proved to be very stable at room temperature, and their band gap is quite stretching-controllable with corresponding laser wavelength varying in the range 870-4590 nm, which is not easy to be implemented via previous techniques. High electro-optical conversion efficiency can be achieved by simply applying electric voltage on the chain ends and the MCC lasers are naturally polarized.
    Keywords: electro-optical; ATK; Application; carbon chain;
    Area: nanowires
    BibTeX: 
    @article{Lin2012,
  author = {Z. Z. Lin and J. Zhuang and X. J. Ning},
  title = {High-efficient tunable infrared laser from monatomic carbon chains},
  journal = {EPL (Europhysics Letters)},
  year = {2012},
  volume = {97},
  number = {2},
  pages = {27006},
  doi = {http://dx.doi.org/10.1209/0295-5075/97/27006}
}
    H.Y. Lv, H.J. Liu, X.J. Tan, L. Pan, Y.W. Wen, J. Shi & X.F. Tang The properties of BiSb nanoribbons from first-principles calculations

    [Abstract] [BibTeX]

    		 2012 Nanoscale
    Vol. 4(2), -     		 DOI  
    Abstract: The structural, electronic and magnetic properties of BiSb nanoribbons (BSNRs) with different widths and edge configurations are investigated via the first-principles pseudopotential method. It is found that the pristine BSNRs with armchair edges (ABSNRs) are semiconductors and the band gaps exhibit a width dependent odd-even oscillation. In contrast, the pristine BSNRs with zigzag edges (ZBSNRs) are found to be metallic. When all the edge atoms are passivated by hydrogen, both the ABSNRs and ZBSNRs become semiconducting and the corresponding band gaps decrease monotonically with the increasing width. If, however, the edge atoms are partially passivated, the ABSNRs can be either semiconducting or metallic. Moreover, local magnetism appears when all the edge Sb atoms are passivated and there are one or more unsaturated Bi atoms. Using the nonequilibrium Green's function (NEGF) approach, we find that all the investigated odd-numbered ABSNRs have almost the same peak value of the power factor around the Fermi level. This is not the case for the even-numbered ABSNRs, where the peaks are twice that of when they are n-type doped. Our calculations indicate that BSNRs can have a very high room temperature figure of merit (ZT value), which makes them very promising candidates for thermoelectric applications.
    Keywords: BiSb nanoribbons; spin; figure of merit; ZT; ab initio molecular-dynamics; nanowires; transport-properties; graphene nanoribbons; semiconductor transition; thermoelectric materials; electronic-structure; thin-films; exfoliation; devices; ATK; Application
    Area: graphene; spin; thermo
    BibTeX: 
    @article{Lv2012,
  author = {Lv, H. Y. and Liu, H. J. and Tan, X. J. and Pan, L. and Wen, Y. W. and Shi, J. and Tang, X. F.},
  title = {The properties of BiSb nanoribbons from first-principles calculations},
  journal = {Nanoscale},
  publisher = {The Royal Society of Chemistry},
  year = {2012},
  volume = {4},
  number = {2},
  pages = {--},
  doi = {http://dx.doi.org/10.1039/C1NR11585E}
}
    Yukihito Matsuura Spin transport in poly(metalarenylsilane)

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(5), 053303     		 DOI  
    Abstract: We focused on the spin transport properties of polymers containing ferrocene and the related transition-metal-benzene sandwich compound (metal=Cr and V) with a silicon bridge such as poly(ferrocenylsilane) and poly(metalarenylsilane). As a model system, a sulfur-substituted oligomer was put on gold electrodes via the sulfur-gold interaction. Spin transport between the two gold electrodes was calculated using a non-equilibrium Green's function formalism and density functional theory. We have found that the oligomer containing Cr or V atoms exhibited an almost perfect spin filter behavior in which all the 3dz2 orbitals contributed to the electron transport.
    Keywords: band structure; density functional theory; Green's function methods; polymers; spin polarised transport; ATK; Application
    Area: molecular electronics; spin
    BibTeX: 
    @article{Matsuura2012,
  author = {Matsuura, Yukihito},
  title = {Spin transport in poly(metalarenylsilane)},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {5},
  pages = {053303},
  doi = {http://dx.doi.org/10.1063/1.3680590}
}
    Zeyuan Ni, Qihang Liu, Kechao Tang, Jiaxin Zheng, Jing Zhou, Rui Qin, Zhengxiang Gao, Dapeng Yu & Jing Lu Tunable Bandgap in Silicene and Germanene

    [Abstract] [BibTeX]

    		 2011 Nano Letters
    Vol. 12(1)Nano Letters, 113-118     		 DOI  
    Abstract: By using ab initio calculations, we predict that a vertical electric field is able to open a band gap in semimetallic single-layer buckled silicene and germanene. The sizes of the band gap in both silicene and germanene increase linearly with the electric field strength. Ab initio quantum transport simulation of a dual-gated silicene field effect transistor confirms that the vertical electric field opens a transport gap, and a significant switching effect by an applied gate voltage is also observed. Therefore, biased single-layer silicene and germanene can work effectively at room temperature as field effect transistors.
    By using ab initio calculations, we predict that a vertical electric field is able to open a band gap in semimetallic single-layer buckled silicene and germanene. The sizes of the band gap in both silicene and germanene increase linearly with the electric field strength. Ab initio quantum transport simulation of a dual-gated silicene field effect transistor confirms that the vertical electric field opens a transport gap, and a significant switching effect by an applied gate voltage is also observed. Therefore, biased single-layer silicene and germanene can work effectively at room temperature as field effect transistors.
    Keywords: Silicene; germanene; band gap; quantum transport; electric field; first-principles calculation; ATK; Application
    Area: semi
    BibTeX: 
    @article{Ni2011,
  author = {Ni, Zeyuan and Liu, Qihang and Tang, Kechao and Zheng, Jiaxin and Zhou, Jing and Qin, Rui and Gao, Zhengxiang and Yu, Dapeng and Lu, Jing},
  title = {Tunable Bandgap in Silicene and Germanene},
  booktitle = {Nano Letters},
  journal = {Nano Letters},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {12},
  number = {1},
  pages = {113--118},
  doi = {http://dx.doi.org/10.1021/nl203065e}
}
    Dan Erik Petersen, Hans Henrik B. Sørensen, Per Christian Hansen, Stig Skelboe & Kurt Stokbro Block tridiagonal matrix inversion and fast transmission calculations

    [Abstract] [BibTeX]

    		 2008 Journal of Computational Physics
    Vol. 227(6), 3174-3190     		 DOI URL 
    Abstract: A method for the inversion of block tridiagonal matrices encountered in electronic structure calculations is developed, with the goal of efficiently determining the matrices involved in the Fisher-Lee relation for the calculation of electron transmission coefficients. The new method leads to faster transmission calculations compared to traditional methods, as well as freedom in choosing alternate Green's function matrix blocks for transmission calculations. The new method also lends itself to calculation of the tridiagonal part of the Green's function matrix. The effect of inaccuracies in the electrode self-energies on the transmission coefficient is analyzed and reveals that the new algorithm is potentially more stable towards such inaccuracies.
    Keywords: Matrix inversion; Electron transport; Transmission; Density functional theory; ATK; Background; Application
    Area:
    BibTeX: 
    @article{Petersen2008,
  author = {Petersen, Dan Erik and Sørensen, Hans Henrik B. and Hansen, Per Christian and Skelboe, Stig and Stokbro, Kurt},
  title = {Block tridiagonal matrix inversion and fast transmission calculations},
  journal = {Journal of Computational Physics},
  year = {2008},
  volume = {227},
  number = {6},
  pages = {3174--3190},
  url = {http://www.sciencedirect.com/science/article/pii/S0021999107005177},
  doi = {http://dx.doi.org/10.1016/j.jcp.2007.11.035}
}
    You Qian, Kai-Tak Lam, Chengkuo Lee & Gengchiau Liang The effects of interlayer mismatch on electronic properties of bilayer armchair graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Carbon
    Vol. 50(4), 1659-1666     		 DOI  
    Abstract: We investigate the impact of interlayer mismatch on the electronic properties of bilayer graphene nanoribbons (BGNRs) with armchair-edges in terms of the total energy and electronic structures by first principle calculations. Simulation results show that in-plane misalignments require little energy and a large variation in the energy bandgap (EG) can be observed. Based on the resulting atomic configurations due to the misalignments, the details of the observed relationship between bandgap and the lattice mismatch are investigated. It is observed that in general, misalignment in the transverse direction results in a decrease in the interaction between the two layers, giving rise to a larger EG. On the other hand, misalignment in the longitudinal direction, i.e. along the edges, leads to an oscillation in EG due to the periodic change of the GNR stacking order. A combination of these movements results in a complex variation of EG, which introduces great uncertainty in electronic devices. However, such a phenomenon could also be used in various kinds of nanoelectromechanical systems as it provides a large change in electronic properties with a small movement.
    Keywords: bilayer graphene nanoribbon; ATK; Application; nanoelectromechanics
    Area: graphene
    BibTeX: 
    @article{Qian2012,
  author = {Qian, You and Lam, Kai-Tak and Lee, Chengkuo and Liang, Gengchiau},
  title = {The effects of interlayer mismatch on electronic properties of bilayer armchair graphene nanoribbons},
  journal = {Carbon},
  year = {2012},
  volume = {50},
  number = {4},
  pages = {1659--1666},
  doi = {http://dx.doi.org/10.1016/j.carbon.2011.12.007}
}
    Yuta Tsuji, Aleksandar Staykov & Kazunari Yoshizawa Molecular Rectifier Based on pi-pi Stacked Charge Transfer Complex

    [Abstract] [BibTeX]

    		 2012 Journal of Physical Chemistry C
    Vol. 116(3)The Journal of Physical Chemistry C, 2575-2580     		 DOI  
    Abstract: Electron transport through pi-stacked materials has been studied theoretically and experimentally so far with versatile applications in mind. In this paper a novel pi-stacked molecular rectifier is proposed. Electron transport properties through cyclophane-type quinhydrone are investigated by using nonequilibrium Green's function method combined with density functional theory. The investigated molecule has a quinhydrone structure comprised of pi-stacked donor (hydroquinone) and acceptor (benzoquinone) pair due to the in-phase orbital interaction between the HOMO of hydroquinone and the LUMO of benzoquinone. A computed current-voltage curve shows rectifying behavior in the direction perpendicular to the ring plane. The maximum value of rectification ratio of 2.37 is obtained at 0.8 V. In this system the LUMO level plays a key role, and asymmetrical evolution of the LUMO level for positive and negative biases leads to the rectifying behavior. The present study is a basic step for further functionalization of a molecular rectifier based on transannular electron transport. The understanding of insight into the electron transport through a pi-stacked system will provide motivation for design of future molecular devices.
    Keywords: molecular electronics; ATK; Application; rectification; molecular devices
    Area: molecular electronics
    BibTeX: 
    @article{Tsuji2011a,
  author = {Tsuji, Yuta and Staykov, Aleksandar and Yoshizawa, Kazunari},
  title = {Molecular Rectifier Based on pi-pi Stacked Charge Transfer Complex},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {3},
  pages = {2575--2580},
  doi = {http://dx.doi.org/10.1021/jp209547a}
}
    Haiqing Wan, Benhu Zhou, Xiongwen Chen, Chang Q. Sun & Guanghui Zhou Switching, Dual Spin-Filtering Effects, and Negative Differential Resistance in a Carbon-Based Molecular Device

    [Abstract] [BibTeX]

    		 2012 Journal of Physical Chemistry C
    Vol. 116(3)The Journal of Physical Chemistry C, 2570-2574     		 DOI  
    Abstract: We present ab initio calculations for spin-dependent electron transport in a molecular device constructed by two carbon chains capped with a phenyl ring, which is sandwiched between two zig-zag-edged graphene nanoribbon (ZGNR) electrodes, where the ZGNRs are modulated by external magnetic field. The coexistence of switching, dual spin-filtering effects, and negative differential resistance (NDR) in the model device is demonstrated with the theory of carbon pi-electrons. Interestingly, a two-state molecular conformational switch can be realized by changing the orientation between the planes of phenyl ring and electrodes, where the majority-spin current modulation (ON/OFF ratio) is 170-479 within the considered bias window. Moreover, the device shows perfect dual spin-filtering effect and can generate and control a full dual spin-polarized current through either the source-drain voltage or magnetic configuration of the electrodes. The selective spin current is due to a dual selection rule, the symmetry match between two ZGNR electrodes spin channel, and the carbon chain's spin selection in our system. In addition, the obvious NDR behavior has also been observed in our model.
    Keywords: ATK; Application; graphene; spin filter; negative differential resistance; NDR;
    Area: graphene; spin
    BibTeX: 
    @article{Wan2011,
  author = {Wan, Haiqing and Zhou, Benhu and Chen, Xiongwen and Sun, Chang Q. and Zhou, Guanghui},
  title = {Switching, Dual Spin-Filtering Effects, and Negative Differential Resistance in a Carbon-Based Molecular Device},
  booktitle = {The Journal of Physical Chemistry C},
  journal = {Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2012},
  volume = {116},
  number = {3},
  pages = {2570--2574},
  doi = {http://dx.doi.org/10.1021/jp2092576}
}
    Jinying Wang, Zhongfan Liu & Zhirong Liu First-principles study of the transport behavior of zigzag graphene nanoribbons tailored by strain

    [Abstract] [BibTeX]

    		 2012 AIP Advances
    Vol. 2(1), 012103     		 DOI  
    Abstract: The charge transport properties of zigzag graphene nanoribbons (ZGNRs) under uniaxial and shear strains are theoretically studied. Although all strained ZGNRs have similar metallic band structures, they show four types of transport behavior under bias voltages that depend on the type of strain and the mirror symmetry of the ZGNR. Under an applied uniaxial strain, the current of symmetric ZGNRs is consistently small, while for asymmetric ZGNRs it is large. In contrast, the current increases with increasing shear strain for symmetric ZGNRs while it decreases for asymmetric ZGNRs. The current properties merge when the shear strain exceeds a critical value, and the two systems then show similar behavior. Our results suggest that strained ZGNRs with an appropriate applied shear are ideal conducting wires.
    Keywords: ab initio calculations; band structure; graphene; strain; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Wang2012,
  author = {Jinying Wang and Zhongfan Liu and Zhirong Liu},
  title = {First-principles study of the transport behavior of zigzag graphene nanoribbons tailored by strain},
  journal = {AIP Advances},
  publisher = {AIP},
  year = {2012},
  volume = {2},
  number = {1},
  pages = {012103},
  doi = {http://dx.doi.org/10.1063/1.3676615}
}
    Xiao-Lin Wei, Yuan-Ping Chen, Wen-Liang Liu & Jian-Xin Zhong Enhanced gas sensor based on nitrogen-vacancy graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Physics Letters A
    Vol. 376(4), 559-562     		 DOI  
    Abstract: We study the electron transport of nitrogen-vacancy zigzag graphene nanoribbons (ZGNRs) absorbing gas molecules. It is found that the nitrogen-vacancy ZGNRs are more sensitive to the gas molecules than the pristine ZGNRs. The gas molecules absorbed on the three-nitrogen vacancies lead to sharp resonant peaks on conductance, while those absorbed on the four-nitrogen vacancies lead to anti-resonant dips. Each kind of gas molecule can be detected by its own unique (different energy) resonant peaks (or dips). This indicates that the nitrogen vacancy can enhance the sensitivity to gas molecules, i.e., nitrogen-vacancy ZGNRs can serve as better gas sensors.
    Keywords: Nitrogen vacancy; Graphene nanoribbons; Electron transport; Gas sensor; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Wei2012,
  author = {Wei, Xiao-Lin and Chen, Yuan-Ping and Liu, Wen-Liang and Zhong, Jian-Xin},
  title = {Enhanced gas sensor based on nitrogen-vacancy graphene nanoribbons},
  journal = {Physics Letters A},
  year = {2012},
  volume = {376},
  number = {4},
  pages = {559--562},
  doi = {http://dx.doi.org/10.1016/j.physleta.2011.10.055}
}
    Yihong Wu, Ying Wang, Jiayi Wang, Miao Zhou, Aihua Zhang, Chun Zhang, Yanjing Yang, Younan Hua & Baoxi Xu Electrical transport across metal/two-dimensional carbon junctions: Edge versus side contacts

    [Abstract] [BibTeX]

    		 2012 AIP Advances
    Vol. 2(1), 012132     		 DOI  
    Abstract: Metal/two-dimensional carbon junctions are characterized by using a nanoprobe in an ultrahigh vacuum environment. Significant differences were found in bias voltage (V) dependence of differential conductance (dI/dV) between edge- and side-contact; the former exhibits a clear linear relationship (i.e., dI/dV propto V), whereas the latter is characterized by a nonlinear dependence, dI/dV propto V^(3/2). Theoretical calculations confirm the experimental results, which are due to the robust two-dimensional nature of the carbon materials under study. Our work demonstrates the importance of contact geometry in graphene-based electronic devices.
    Keywords: metal-insulator boundaries; graphene; experimental comparison; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Wu2012,
  author = {Wu, Yihong and Wang, Ying and Wang, Jiayi and Zhou, Miao and Zhang, Aihua and Zhang, Chun and Yang, Yanjing and Hua, Younan and Xu, Baoxi},
  title = {Electrical transport across metal/two-dimensional carbon junctions: Edge versus side contacts},
  journal = {AIP Advances},
  publisher = {AIP},
  year = {2012},
  volume = {2},
  number = {1},
  pages = {012132},
  doi = {http://dx.doi.org/10.1063/1.3684617}
}
    J. Zhou, L. Wang, R. Qin, J.X. Zheng, W.N. Mei, P.A. Dowben, S. Nagase, Z.X. Gao & J. Lu Structure and Electronic and Transport Properties of Transition Metal Intercalated Graphene and Graphene-Hexagonal-Boron-Nitride Bilayer

    [Abstract] [BibTeX]

    		 2011 Journal of Physical Chemistry C
    Vol. 115(51), 25273-25280     		 DOI  
    Abstract: Structural, electronic, and magnetic properties of the Fe-, Co-, Ni-, and V-intercalated graphene bilayer sandwich (denoted by C(2)vertical bar M vertical bar C(2), M = Fe, Co, Ni, and V) and graphene on hexagonal boron nitride (h-BN) bilayer sandwich (denoted by C(2)vertical bar M vertical bar BN, M = Fe, Co, Ni, and V) are studied by using density functional theory method. We find that both the graphene bilayer and graphene-h-BN bilayer in all the C(2)vertical bar M vertical bar C(2) and C(2)vertical bar M vertical bar BN sandwiches favor AB stacking over AA stacking mode. The Fe, Co, and Ni atoms prefer to be located over the center of C-C bonds whereas V atoms prefer to be located above the C atoms on graphene, and they all prefer to be located above the N atoms on h-BN sheet, regardless of the stacking mode. The C(2)vertical bar Fe vertical bar C(2), C(2)vertical bar CO vertical bar C(2), C(2)vertical bar Fe vertical bar BN, and C(2)vertical bar Co vertical bar BN sandwiches of AB stacking are all ferromagnetic metals with the spin polarization of 86%, 67%, 65%, and 46% at the Fermi level, respectively. By contrast, both C(2)vertical bar Ni vertical bar C(2) and C(2)vertical bar Ni vertical bar BN sandwiches of AB stacking are nonmagnetic semiconductors with bandgaps of 0.64 and 0.23 eV, respectively, which provide a novel strategy of opening a bandgap of graphene. From the quantum transport calculation, we obtain a giant room-temperature magnetoresistance of similar to 200% in the spin valve device based on AB stacking C(2)vertical bar Fe vertical bar C(2) sandwich.
    Keywords: field-effect transistors; room-temperature; magnetoresistance; graphite; gap; graphene bilayer; boron-nitride; Application; ATK
    Area: graphene; spin
    BibTeX: 
    @article{Zhou2011b,
  author = {Zhou, J. and Wang, L. and Qin, R. and Zheng, J. X. and Mei, W. N. and Dowben, P. A. and Nagase, S. and Gao, Z. X. and Lu, J.},
  title = {Structure and Electronic and Transport Properties of Transition Metal Intercalated Graphene and Graphene-Hexagonal-Boron-Nitride Bilayer},
  journal = {Journal of Physical Chemistry C},
  publisher = {Amer Chemical Soc},
  year = {2011},
  volume = {115},
  number = {51},
  pages = {25273--25280},
  doi = {http://dx.doi.org/10.1021/jp209468f}
}
    Zhaoqiang Bai, Yongqing Cai, Lei Shen, Ming Yang, Viloane Ko, Guchang Han & Yuanping Feng Magnetic and transport properties of Mn[sub 3 - x]Ga/MgO/Mn[sub 3 - x]Ga magnetic tunnel junctions: A first-principles study

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(2), 022408     		 DOI  
    Abstract: Magnetic and transport properties of Mn[3-x]Ga/MgO/Mn[3-x]Ga (0<=x<=1) magnetic tunnel junctions are studied using first-principles approach based on density functional theory and non-equilibrium Green's function. Perpendicular magnetization, of which the magnetic anisotropy energy reaches more than 1 meV/unit-cell, is confirmed to be energetically favoured by both Mn2Ga and Mn3Ga thin films. Furthermore, despite high spin-polarization at the Fermi energy for both these compounds as reported, our transport calculation shows considerable disparity in the transmission behaviour between Mn2Ga/MgO/Mn2Ga(001) and Mn3Ga/MgO/Mn_3Ga(001) magnetic tunnel junctions: huge optimistic tunneling magnetoresistance ratio of 103% for the former, and nevertheless, no tunneling magnetoresistance effect absolutely for the latter. This phenomenon is attributed to the symmetry selective filtering effect of the MgO spacer. On this premise, Mn[3-x]Ga compounds with low Mn concentration are predicted to be promising candidate materials to serve as the electrodes of spin-transfer torque devices in the next-generation data storage technique.
    Keywords: ab initio calculations; density functional theory; Fermi level; gallium alloys; Green's function methods; magnesium compounds; magnetic multilayers; magnetic thin films; manganese alloys; MIM structures; perpendicular magnetic anisotropy; spin polarised transport; tunnelling magnetoresistance; ATK; Application
    Area: interfaces; spin; semi; nvm
    BibTeX: 
    @article{Bai2012,
  author = {Zhaoqiang Bai and Yongqing Cai and Lei Shen and Ming Yang and Viloane Ko and Guchang Han and Yuanping Feng},
  title = {Magnetic and transport properties of Mn[sub 3 - x]Ga/MgO/Mn[sub 3 - x]Ga magnetic tunnel junctions: A first-principles study},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {2},
  pages = {022408},
  doi = {http://dx.doi.org/10.1063/1.3676195}
}
    Changfeng Fang, Dongmei Li, Bin Cui, Yuqing Xu, Guomin Ji & Desheng Liu Effect of different electrodes on Fano resonance in molecular devices

    [Abstract] [BibTeX]

    		 2012 Applied Physics Letters
    Vol. 100(2), 023303     		 DOI  
    Abstract: By using nonequilibrium Green's function in combination with density functional theory, we study the electronic transport properties of two typical pi-conjugated molecules (dithiol-benzene and C4S2), sandwiched between two metallic electrodes made of different metals. The presence of two different electrodes leads to Fano resonances at certain energy. As a consequence, electronic transport in future molecular electric circuits can be substantially affected when the molecular devices placed between electrodes with different chemical potentials. The Fano line shapes reveal that there is nonresonant channel when two asymmetric electrodes are employed.
    Keywords: density functional theory; electrodes; electron spin polarisation; Green's function methods; molecular electronics; photoemission; ATK; Application
    Area: molecular electronics; spin
    BibTeX: 
    @article{Fang2012,
  author = {Changfeng Fang and Dongmei Li and Bin Cui and Yuqing Xu and Guomin Ji and Desheng Liu},
  title = {Effect of different electrodes on Fano resonance in molecular devices},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2012},
  volume = {100},
  number = {2},
  pages = {023303},
  doi = {http://dx.doi.org/10.1063/1.3676190}
}
    Yukihito Matsuura Spin transport in bimetallic pentalene complexes

    [Abstract] [BibTeX]

    		 2011 Solid State Communications
    Vol. 151(24), 1877 - 1880     		 DOI  
    Abstract: Spin transport in bimetallic pentalene complexes (CpM(pentalene)M'Cp;M,M'=Fe,Co,Ni) between two gold electrodes was investigated, using a Green's function formalism under density functional theory. Variation of the metal atom species in the complexes gives a considerable change in their spin properties, with hetero-bimetallic complexes containing an odd number of electrons exhibiting spin filter behaviour. In contrast, alternation in the contact condition, whether Cp-anchoring or adducting by sulphur-gold bonds, had almost no effect on spin filter behaviour, but did lead to variation in electrical conduction. We examined suitable bimetallic pentalene complexes in order to enhance their spin filter efficiency.
    Keywords: Bimetallic pentalene complex; spin transport; DFT; ATK; Application; molecular electronics
    Area: molecular electronics; spin
    BibTeX: 
    @article{Matsuura2011,
  author = {Yukihito Matsuura},
  title = {Spin transport in bimetallic pentalene complexes},
  journal = {Solid State Communications},
  year = {2011},
  volume = {151},
  number = {24},
  pages = {1877 - 1880},
  doi = {http://dx.doi.org/10.1016/j.ssc.2011.10.001}
}
    Yongqing Cai, Aihua Zhang, Yuan Ping Feng & Chun Zhang Switching and rectification of a single light-sensitive diarylethene molecule sandwiched between graphene nanoribbons

    [Abstract] [BibTeX]

    		 2011 The Journal of Chemical Physics
    Vol. 135(18), 184703     		 DOI URL 
    Abstract: The "open" and "closed" isomers of the diarylethene molecule that can be converted between each other upon photo-excitation are found to have drastically different current-voltage characteristics when sandwiched between two graphene nanoribbons (GNRs). More importantly, when one GNR is metallic and another one is semiconducting, strong rectification behavior of the "closed" diarylethene isomer with the rectification ratio >10^3 is observed. The surprisingly high rectification ratio originates from the band gap of GNR and the bias-dependent variation of the lowest unoccupied molecular orbital of the diarylethene molecule, the combination of which completely shuts off the current at positive biases. Results presented in this paper may form the basis for a new class of molecular electronic devices.
    Keywords: graphene nanoribbon; molecular electronic states; nanostructured materials; optical materials; rectification; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Cai2011a,
  author = {Yongqing Cai and Aihua Zhang and Yuan Ping Feng and Chun Zhang},
  title = {Switching and rectification of a single light-sensitive diarylethene molecule sandwiched between graphene nanoribbons},
  journal = {The Journal of Chemical Physics},
  publisher = {AIP},
  year = {2011},
  volume = {135},
  number = {18},
  pages = {184703},
  url = {http://arxiv.org/abs/1111.1811},
  doi = {http://dx.doi.org/10.1063/1.3657435}
}
    C. Cao, L.N. Chen, D. Zhang, W.R. Huang, S.S. Ma & H. Xu Electronic properties and conductance suppression of defected and doped zigzag graphene nanoribbons

    [Abstract] [BibTeX]

    		 2012 Solid State Communications
    Vol. 152(1), 45 - 49     		 DOI  
    Abstract: By using the first-principles calculation based on density functional theory, we investigate the electronic structures and transport properties of the defected and doped zigzag graphene nanoribbons (ZGNRs). The effects of multivacancies defects and impurities have been considered. The results show that band structures of ZGNRs can be tuned strongly and currents drop drastically due to the defect and impurities. Moreover, the notable suppression of conductance can be found near the Fermi level, leading to the negative differential resistance (NDR) behavior under low bias. This effect presents a possibility in novel nanoelectronics devices application.
    Keywords: graphene nanoribbons; electronic structures and transport property; impurity; defect; first-principles; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Cao2012,
  author = {C. Cao and L.N. Chen and D. Zhang and W.R. Huang and S.S. Ma and H. Xu},
  title = {Electronic properties and conductance suppression of defected and doped zigzag graphene nanoribbons},
  journal = {Solid State Communications},
  year = {2012},
  volume = {152},
  number = {1},
  pages = {45 - 49},
  doi = {http://dx.doi.org/10.1016/j.ssc.2011.10.004}
}
    Jianming Jia, Shin-Pon Ju, Daning Shi & Kuan-Fu Lin Electromechanical Response of a SiC Nanotube under Local Torsional Deformation

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(49), 24347-24352     		 DOI  
    Abstract: The electromechanical properties of a SiC nanotube under local torsional deformation have been characterized for the single-walled (7,0) zigzag model using a combined formalism of density functional theory and nonequilibrium Green's function. It is shown that, with the increase of torsion angle, the SiC nanotube undergoes, in turn, the structural evolution with the circular section retained and torsional buckling until complete failure. The local deformation has a significant effect on the transport properties of the nanotube, resulting in the torsion-dependent transport spectrum and current–voltage characteristics. The variation of the current at a given bias with the torsion angle can be attributed to the local-torsion-induced energy shift of edge states in the twisted region of the SiC nanotube.
    Keywords: ATK; Application; SiC nanotube; electromechanical properties;
    Area: nanotubes
    BibTeX: 
    @article{Jia2011,
  author = {Jia, Jianming and Ju, Shin-Pon and Shi, Daning and Lin, Kuan-Fu},
  title = {Electromechanical Response of a SiC Nanotube under Local Torsional Deformation},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {49},
  pages = {24347-24352},
  doi = {http://dx.doi.org/10.1021/jp207857e}
}
    Xiao-Fei Li, Ling-Ling Wang, Ke-Qiu Chen & Yi Luo Tuning the Electronic Transport Properties of Zigzag Graphene Nanoribbons via Hydrogenation Separators

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(49), 24366-24372     		 DOI  
    Abstract: Hydrogenation technique is known to be useful for opening up the band gap and controlling the electronic properties of the graphene. We have demonstrated with first principles calculations that the hydrogenation can be used to make separators to electrically separate zigzag graphene nanoribbons (zGNR) and tune their transport properties. First principles calculations reveal that each hydrogenation separator can introduce two conducting edge-like states into the subbands around the Fermi level, which can greatly enhance the conductance of the system. We find that the zGNRs with hydrogenation separators are still spin polarized; the distributions of spin densities are mainly located along the two edges of the pristine nanoribbon and the borders of the separators. The current polarization shows a nice oscillation behavior as a function of the position of the separator, which originates from the symmetry dependent transport character of the zGNRs. Moreover, we find that the hydrogenation separators can screen the impact of rough edges, which makes rough-edge zGNRs behave like smooth-edge zGNRs. Our findings could be very useful for designing electronic devices based on the hydrogenation of graphene nanoribbons.
    Keywords: ATK; Application; graphene nanoribbon; hydrogenation; spin
    Area: graphene; spin
    BibTeX: 
    @article{Li2011f,
  author = {Li, Xiao-Fei and Wang, Ling-Ling and Chen, Ke-Qiu and Luo, Yi},
  title = {Tuning the Electronic Transport Properties of Zigzag Graphene Nanoribbons via Hydrogenation Separators},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {49},
  pages = {24366-24372},
  doi = {http://dx.doi.org/10.1021/jp208892h}
}
    Haiying Liu, Genqin Li, Hongqi Ai, Jilai Li & Yuxiang Bu Electronic Enhancement Effect of Copper Modification of Base Pairs on the Conductivity of DNA

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(45), 22547-22556     		 DOI  
    Abstract: The effect of the new designed multicopper modification of base pairs on the conductivity of DNA was investigated by the nonequilibrium Green's function method combined with density functional theory. Electronic transport calculations revealed that the equi-number H-by-Cu replacement can significantly enhance the conductivity of DNA from two aspects: transverse base-to-base communication along the hydrogen-bond direction and longitudinal transport along the DNA duplex. Furthermore, the enhancement effect on the longitudinal direction is more notable than that on the transverse. A tunneling mechanism is suggested for the short DNA segments. The decay factor of conductance in Cu-DNA decreases by half compared with the native DNA, thus making it more promising for constructing nanowires. In addition, Cu-DNA may prefer electron migration to hole transport with the lengthening of DNA segments. This work will shed some light on the design of promising DNA-based molecular wires.
    Keywords: ATK; Application; molecular electronics; DNA base pairs;
    Area: molecular electronics
    BibTeX: 
    @article{Liu2011f,
  author = {Liu, Haiying and Li, Genqin and Ai, Hongqi and Li, Jilai and Bu, Yuxiang},
  title = {Electronic Enhancement Effect of Copper Modification of Base Pairs on the Conductivity of DNA},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {45},
  pages = {22547-22556},
  doi = {http://dx.doi.org/10.1021/jp2070198}
}
    E. Nadimi, P. Planitz, R. Ottking, M. Schreiber & C. Radehaus First-principles investigation of the leakage current through strained SiO2 gate dielectrics in MOSFETs

    [Abstract] [BibTeX]

    		 2011 Semiconductor Conference Dresden (SCD), 2011, 1-4  DOI  
    Abstract: A combination of density functional theory and non-equilibrium Green's function formalism has been applied to the atomic scale calculation of the leakage current through the strained SiO2 dielectric layer of MOSFETs. This first-principles approach accounts for intrinsic strain at the Si/SiO2 interface as well as its influence on the leakage current. Furthermore, the impact of external mechanical stress on the leakage current was investigated. It is shown that compression of atomic layers along the direction perpendicular to the interface results in a lower tunneling probability and leakage current while the tensile strain in that direction leads to higher tunneling probability and consequently higher leakage current. Based on this behavior we give an explanation for the increase of the tunneling effective mass of electrons as the thickness of the dielectric layer decreases in terms of intrinsic strain at the Si/SiO2 interface.
    Keywords: MOSFET; Si-SiO2; atomic layers; density functional theory; dielectric layer; external mechanical stress; first-principles investigation; intrinsic strain; leakage current; nonequilibrium Green function formalism; strained gate dielectrics; tensile strain; tunneling effective mass; tunneling probability; Green's function methods; MOSFET; leakage currents; silicon compounds; tunnelling; ATK; Application; interface
    Area: interfaces; semi
    BibTeX: 
    @inproceedings{Nadimi2011,
  author = {Nadimi, E. and Planitz, P. and Ottking, R. and Schreiber, M. and Radehaus, C.},
  title = {First-principles investigation of the leakage current through strained SiO2 gate dielectrics in MOSFETs},
  booktitle = {Semiconductor Conference Dresden (SCD), 2011},
  year = {2011},
  pages = {1-4},
  doi = {http://dx.doi.org/10.1109/SCD.2011.6068768}
}
    Y.-H. Tang, V.M.K. Bagci, Jing-Han Chen & Chao-Cheng Kaun Conductance of Stretching Oligothiophene Single-Molecule Junctions: A First-Principles Study

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(50), 25105-25108     		 DOI  
    Abstract: We analyze conductance switching properties during the stretching of Au-oligothiophene dimethylene dithiol-Au single-molecule junctions, by using first-principles calculations based on the density functional theory and the nonequilibrium Green's function approach. Our results of these sigma-pi hybrid molecular systems agree well with the experimental data and confirm that the longer molecular junction (four thiophene rings) has higher conductance than the shorter one (three thiophene rings). We attribute this behavior to their differently located molecular levels, with respect to the Fermi energy, at the point of the junction break. This breaking point, occurring at a longer stretching distance for the shorter molecule, affects the junction conductance significantly and can be determined by several characteristics of the junction.
    Keywords: ATK; Application; molecular electronics; switching;
    Area: molecular electronics
    BibTeX: 
    @article{Tang2011,
  author = {Tang, Y.-H. and Bagci, V. M. K. and Chen, Jing-Han and Kaun, Chao-Cheng},
  title = {Conductance of Stretching Oligothiophene Single-Molecule Junctions: A First-Principles Study},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {50},
  pages = {25105-25108},
  doi = {http://dx.doi.org/10.1021/jp209671v}
}
    Zhongchang Wang, Mitsuhiro Saito, Susumu Tsukimoto & Yuichi Ikuhara Heterointerfaces: atomic structures, electronic states, and related properties

    [Abstract] [BibTeX]

    		 2011 Journal of the Ceramic Society of Japan
    Vol. 119(1395), 783-793     		 DOI  
    Abstract: Recent breakthroughs in transmission electron microscopy enable a direct quantitative determination of the technologically significant heterointerfaces, yet a direct interpretation is not always possible. Here, we review the general processes to introduce the high-precision first-principles calculations into the microscopy in order to obtain an atomistic understanding of effects of buried interfaces on a wide range of properties. We demonstrate the possibility and important advance of this combined method in relating interface structures to device physics even for the complex heterointerfaces, SiC/Ti3SiC2, La[x]Sr[1-x]O/(SrTiO3)n, and Pd/ZnO presented here. We therefore believe that this approach should be widely applicable to many other interfaces and a range of materials, providing new insights into many long-standing unresolved issues regarding interfaces.
    Keywords: ATK; Application; buried interfaces; experimental comparison
    Area: interfaces; semi
    BibTeX: 
    @article{Wang2011c,
  author = {Zhongchang Wang and Mitsuhiro Saito and Susumu Tsukimoto and Yuichi Ikuhara},
  title = {Heterointerfaces: atomic structures, electronic states, and related properties},
  journal = {Journal of the Ceramic Society of Japan},
  year = {2011},
  volume = {119},
  number = {1395},
  pages = {783-793},
  doi = {http://dx.doi.org/10.2109/jcersj2.119.783}
}
    Lu Wang, Jiaxin Zheng, Jing Zhou, Rui Qin, Hong Li, Wai-Ning Mei, Shigeru Nagase & Jing Lu Tuning graphene nanoribbon field effect transistors via controlling doping level

    [Abstract] [BibTeX]

    		 2011 Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)
    Vol. 130, 483-489     		 DOI  
    Abstract: By performing first-principles transport simulations, we demonstrate that n-type transfer curves can be obtained in armchair-edged graphene nanoribbon field effect transistors by the potassium atom and cobaltocene molecule doping, or substituting the carbon by nitrogen atom. The Dirac point shifts downward from 0 to -12 V when the n-type impurity concentration increases from 0 to 1.37%, while the transfer curves basically maintain symmetric feature with respect to the Dirac point. In general, the on/off current ratios are decreased and subthreshold swings are increased with the increasing doping level. Therefore, the performance of armchair-edged graphene nanoribbon field effect transistors can be controlled via tuning the impurity doping level.
    Keywords: graphene nanoribbon; field effect transistor; ab initio calculation; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Wang2011d,
  author = {Wang, Lu and Zheng, Jiaxin and Zhou, Jing and Qin, Rui and Li, Hong and Mei, Wai-Ning and Nagase, Shigeru and Lu, Jing},
  title = {Tuning graphene nanoribbon field effect transistors via controlling doping level},
  journal = {Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)},
  publisher = {Springer Berlin / Heidelberg},
  year = {2011},
  volume = {130},
  pages = {483-489},
  doi = {http://dx.doi.org/10.1007/s00214-011-1026-5}
}
    Yuqing Xu, Changfeng Fang, Guomin Ji, Wei Du, Dongmei Li & Desheng Liu Electrostatic current switching and negative differential resistance behavior in a molecular device based on carbon nanotubes

    [Abstract] [BibTeX]

    		 2012 Phys. Chem. Chem. Phys.
    Vol. 14(2), 668-674     		 DOI  
    Abstract: The electronic transport properties of an all-carbon mechanically controlled molecular device based on carbon nanotubes are studied using non-equilibrium Green's function in combination with density functional theory. A segment of (10,0) single-walled carbon nanutube (SWCNT) is placed concentrically outside a (5,0) SWCNT, namely, a (5,0)@(10,0) double-walled carbon nanotube (DWCNT). It is found that the position, orientation and length scaling of the (10,0) SWCNT have crucial effects on the electronic transport properties of the system. When the (10,0) SWCNT is mechanically pushed forward along the axial direction, alternation of on/off switching behavior under low bias and negative differential resistance behavior under high bias are observed. Significant changes in the electronic transport properties arise when rotating the (10,0) SWCNT around the common axis or adding carbon atom layers in the transport direction. Theoretical explanations are proposed for these phenomena.
    Keywords: ATK; Application; nanotube; mechanically controlled molecular device;
    Area: nanotubes
    BibTeX: 
    @article{Xu2012,
  author = {Xu, Yuqing and Fang, Changfeng and Ji, Guomin and Du, Wei and Li, Dongmei and Liu, Desheng},
  title = {Electrostatic current switching and negative differential resistance behavior in a molecular device based on carbon nanotubes},
  journal = {Phys. Chem. Chem. Phys.},
  year = {2012},
  volume = {14},
  number = {2},
  pages = {668-674},
  doi = {http://dx.doi.org/10.1039/C1CP22882J}
}
    Shan-Sheng Yu, Chun Wang, Wei-Tao Zheng & Qing Jiang Mechanical and electron-transport properties of graphene nanoribbons under tensile strain: A first-principles study

    [Abstract] [BibTeX]

    		 2011 physica status solidi (a)
    Vol. 208(10), 2328-2331     		 DOI  
    Abstract: We calculate the mechanical and electron-transport properties of graphene nanoribbons (GNRs) under uniaxial tensile strain with first-principles density functional theory. Our calculations reveal that armchair- and zigzag-shaped edges decrease and increase the tensile strength of GNR, respectively. The I-V curve for GNR with armchair edges changes drastically under tensile strain, while the influence of tensile strain on the electron-transport properties of GNR with zigzag edges is negligible. Our calculations propose one way to design and fabricate nanoscale mechanical sensors and devices based on GNRs.
    Keywords: ATK; Application; density functional theory; electronic structure; graphene nanoribbons; mechanical properties; molecular electronic devices; transport; magnetoresistance; nanoribbons
    Area: graphene
    BibTeX: 
    @article{Yu2011d,
  author = {Yu, Shan-Sheng and Wang, Chun and Zheng, Wei-Tao and Jiang, Qing},
  title = {Mechanical and electron-transport properties of graphene nanoribbons under tensile strain: A first-principles study},
  journal = {physica status solidi (a)},
  publisher = {WILEY-VCH Verlag},
  year = {2011},
  volume = {208},
  number = {10},
  pages = {2328--2331},
  doi = {http://dx.doi.org/10.1002/pssa.201084168}
}
    Lili Yu, Xin Yan, Hong Li, Rui Qin, Guangfu Luo, Chengyong Xu, Jiaxin Zheng, Qihang Liu, Jing Lu, Zhengxiang Gao & Xuefeng Wang Negative rectification and negative differential resistance in nanoscale single-walled carbon nanotube p-n junctions

    [Abstract] [BibTeX]

    		 2011 Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)
    Vol. 130, 353-359     		 DOI  
    Abstract: We investigate the transport properties of few-nm-long single-walled carbon nanotube (SWCNT) p - n junctions for the first time by using ab initio quantum transport calculations. Unlike the previously reported few-micrometer-long SWCNT p - n junctions, which rectify positively, all the investigated ultrashort SWCNT p - n junctions show negative rectification effect, accompanied by negative differential resistance.
    Keywords: single-walled carbon nanotube; p-n junctions; rectification; negative differential resistance; NDR; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Yu2011e,
  author = {Yu, Lili and Yan, Xin and Li, Hong and Qin, Rui and Luo, Guangfu and Xu, Chengyong and Zheng, Jiaxin and Liu, Qihang and Lu, Jing and Gao, Zhengxiang and Wang, Xuefeng},
  title = {Negative rectification and negative differential resistance in nanoscale single-walled carbon nanotube p-n junctions},
  journal = {Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)},
  publisher = {Springer Berlin / Heidelberg},
  year = {2011},
  volume = {130},
  pages = {353-359},
  doi = {http://dx.doi.org/10.1007/s00214-011-0990-0}
}
    Jing Zeng, Ke-Qiu Chen, Jun He, Xiao-Jiao Zhang & Chang Q. Sun Edge Hydrogenation-Induced Spin-Filtering and Rectifying Behaviors in the Graphene Nanoribbon Heterojunctions

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(50), 25072-25076     		 DOI  
    Abstract: By using nonequilibrium Green's functions in combination with the density functional theory, we investigate the electronic transport properties of edge hydrogenated zigzag-edged graphene nanoribbon heterojunctions. Results show that a perfect spin-filtering effect with 100% spin polarization and a rectifying behavior with a ratio larger than 10^5 can be realized by dihydrogenation, which can also be modulated by changing the widths of the two component ribbons.
    Keywords: ATK; Application; graphene nanoribbon heterojunction; spin filter; hydrogenation; rectification
    Area: graphene; spin
    BibTeX: 
    @article{Zeng2011g,
  author = {Zeng, Jing and Chen, Ke-Qiu and He, Jun and Zhang, Xiao-Jiao and Sun, Chang Q.},
  title = {Edge Hydrogenation-Induced Spin-Filtering and Rectifying Behaviors in the Graphene Nanoribbon Heterojunctions},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {50},
  pages = {25072-25076},
  doi = {http://dx.doi.org/10.1021/jp208248v}
}
    P. Zhao, D.S. Liu & M. Yuan Rectifying properties of a boron/nitrogen-doped C131-based molecular junction: A first-principles study

    [Abstract] [BibTeX]

    		 2012 Physica B: Condensed Matter
    Vol. 407(1), 73 - 76     		 DOI  
    Abstract: Using first-principles density functional theory and non-equilibrium Green's function formalism for quantum transport calculation, we have investigated the electronic transport properties of the boron/nitrogen-doped C131-based molecular junction. Our results show that an obvious rectifying behavior is observed. Moreover, the rectifying performance can be tuned by adjusting the doping sites. The mechanism for the rectifying phenomenon is suggested. The present findings could be helpful for the application of the C131 molecule in the field of single molecular devices or nanometer electronics.
    Keywords: doping; fullerene; molecular electronics; rectification; ATK; Application
    Area: molecular electronics; fullerenes
    BibTeX: 
    @article{Zhao2012,
  author = {P. Zhao and D. S. Liu and M. Yuan},
  title = {Rectifying properties of a boron/nitrogen-doped C131-based molecular junction: A first-principles study},
  journal = {Physica B: Condensed Matter},
  year = {2012},
  volume = {407},
  number = {1},
  pages = {73 - 76},
  doi = {http://dx.doi.org/10.1016/j.physb.2011.09.123}
}
    Ping Bai, Kai Tak Lam, Erping Li & K.K. f. Chang A Comprehensive Atomic Study of Carbon Nanotube Schottky Diode Using First Principles Approach

    [Abstract] [BibTeX]

    		 2007 Electron Devices Meeting, 2007. IEDM 2007. IEEE International, 749-752  DOI  
    Abstract: In this paper, Carbon nanotube (CNT) Schottky diodes are investigated from the atomic perspective using the first principles DFT-NEGF method. Two atomic models are built based on experimental setting. The atomic behaviors of the CNT Schottky diodes are explored through density of states and charge transfer of the atomic models. The electron transport properties of the CNT diodes are analyzed through transmission function, energy gap shifting and I-V characteristics.
    Keywords: DFT-NEGF method; I-V characteristics; atomic models; carbon nanotube Schottky diode; charge transfer; comprehensive atomic study; energy gap shifting; Schottky diodes; carbon nanotubes; charge exchange; ATK; Application
    Area: nanotubes
    BibTeX: 
    @inproceedings{Bai2007a,
  author = {Ping Bai and Kai Tak Lam and Erping Li and Chang, K.K.-f.},
  title = {A Comprehensive Atomic Study of Carbon Nanotube Schottky Diode Using First Principles Approach},
  booktitle = {Electron Devices Meeting, 2007. IEDM 2007. IEEE International},
  publisher = {IEEE, 345 E 47th St, New York, NY 10017 USA},
  year = {2007},
  pages = {749-752},
  doi = {http://dx.doi.org/10.1109/IEDM.2007.4419055}
}
    S. Choudhary & S. Qureshi Vacancy Defect Reconstruction and its Effect on Electron Transport in Si-c Nanotubes

    [Abstract] [BibTeX]

    		 2011 J. Nano- Electron. Phys.
    Vol. 3(1), 1035-1040     		 URL 
    Abstract: We investigate the vacancy defect reconstruction and its effect on I-V characteristics in a (4, 0) zigzag and (5, 5) armchair silicon-carbide nanotubes (SiCNTs) by applying self consistent non-equilibrium Green's function formalism in combination with the density-functional theory to a two probe molecular junction constructed from SiCNTs. The results show that single vacancies and di-vacancies in SiCNTs have different reconstructions. A single vacancy when optimized, reconstructs into a 5-1DB configuration in both zigzag and armchair SiCNTs, and a di-vacancy reconstructs into a 5-8-5 configuration in zigzag and into a 5-2DB configuration in armchair SiCNTs. Introduction of vacancy increases the band gap of (4, 0) metallic SiCNT and decreases the bandgap of (5, 5) semiconducting SiCNT, bias voltage dependent current characteristic show reduction in overall current in metallic SiCNT and an increase in overall current in semiconducting SiCNT.
    Keywords: nanotube; sicnt; armchair-zigzag; defects; vacancy; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Choudhary2011c,
  author = {Choudhary, S. and Qureshi, S.},
  title = {Vacancy Defect Reconstruction and its Effect on Electron Transport in Si-c Nanotubes},
  journal = {J. Nano- Electron. Phys.},
  publisher = {World Scientific Publ Co Pte Ltd},
  year = {2011},
  volume = {3},
  number = {1},
  pages = {1035-1040},
  url = {http://jnep.sumdu.edu.ua/en/component/content/full_article/287}
}
    Haixia Da, Yuan Ping Feng & Gengchaiu Liang Transition-Metal-Atom-Embedded Graphane and Its Spintronic Device Applications

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(46), 22701-22706     		 DOI  
    Abstract: First-principles calculations are implemented to investigate the electronic and magnetic properties of transition-metal (TM)-atom-embedded graphanes. We find that most of the configurations possess magnetic ground states that have larger magnetic moments compared to embedding TM atoms in graphenes. Furthermore, the various magnetic moments can be generated by tailoring the different dopants. We also design a heterojunction structure with nickel- and vanadium-embedded graphanes in order to manipulate the spin currents. Due to the materials' unique characteristics, the spin-down current can be totally suppressed while the spin-up current appears under a negative bias voltage, resulting in a perfect spin filter and spin current diode. Such properties imply promising potential applications in graphane-based nanodevices and spintronics.
    Keywords: ATK; Application; graphene; graphane; transition metals; magnetic moment; spin;
    Area: graphene; spin
    BibTeX: 
    @article{Da2011,
  author = {Da, Haixia and Feng, Yuan Ping and Liang, Gengchaiu},
  title = {Transition-Metal-Atom-Embedded Graphane and Its Spintronic Device Applications},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {46},
  pages = {22701-22706},
  doi = {http://dx.doi.org/10.1021/jp203506z}
}
    Z.Q. Fan & K.Q. Chen Theoretical Investigation of Gate Voltage Controllable Transport Properties In Single C(60) Molecular Device

    [Abstract] [BibTeX]

    		 2011 International Journal of Modern Physics B
    Vol. 25(29), 3871-3880     		 DOI  
    Abstract: The effect of gate voltage on electronic transport properties in single C(60) molecular device is investigated by a first-principles method based on density functional theory and nonequilibrium Green's function formalism. The calculated results show that the variation of the equilibrium conductance with gate voltage strongly corresponds with the variation of transmission eigenvalues and depends on the shift of molecular orbitals. The positive gate voltage can enhance the device's electronic transport, while negative gate voltage weaken it, which shows a gate-controlled molecular current switch. More importantly, the negative differential resistance behavior is observed and can be modulated by the gate potential. A detailed explanations for these phenomena are given.
    Keywords: field-effect transistors; negative differential-resistance; electron-transport; intermolecular interaction; carbon nanotubes; room-temperature; conductance; junctions; 1st-principles; oscillations; ATK; Application; gates; fullerene
    Area: fullerenes
    BibTeX: 
    @article{Fan2011b,
  author = {Fan, Z. Q. and Chen, K. Q.},
  title = {Theoretical Investigation of Gate Voltage Controllable Transport Properties In Single C(60) Molecular Device},
  journal = {International Journal of Modern Physics B},
  publisher = {World Scientific Publ Co Pte Ltd},
  year = {2011},
  volume = {25},
  number = {29},
  pages = {3871--3880},
  doi = {http://dx.doi.org/10.1142/S0217979211102034}
}
    C.X. Zhang, Chaoyu He, Zhizhou Yu, K.W. Zhang, L.Z. Sun & Jianxin Zhong Transport Properties of Zigzag Graphene Nanoribbons Decorated by Carboxyl Group Chains

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(44), 21893-21898     		 DOI URL 
    Abstract: The transport properties of zigzag graphene nanoribbons (ZGNRs) decorated by carboxyl group (OH) chains are systematically investigated using the density functional theory in combination with the nonequilibrium Green's function method. ZGNRs with nine zigzag carbon chains (9ZGNR) decorated by mOH (m is the number of oxidized carbon chains) are taken as typical systems. We find that the OH chains can effectively modulate the electronic structures and transport properties of the 9ZGNR. The systems behave as metal when m <= 4, and a transmission plateau up to 6G0 is found around the Fermi level when m = 3. However, when m > 4, the 9ZGNR-mOH systems become semiconductors. Interestingly, 9ZGNR-7OH and 9ZGNR-8OH behave as n-type semiconductors. It is found that such modulation depends on the edge states as well as the oxygen atoms at the interface. When the width of undecorated carbon regions is <3, Peierls instability induces the metal-semiconductor transition.
    Keywords: ATK; Application; graphene; total-energy calculations; augmented-wave method; graphite oxide; basis-set; phase; films; gas; Peierls instability; metal-semiconductor transition
    Area: graphene
    BibTeX: 
    @article{Zhang2011f,
  author = {Zhang, C. X. and He, Chaoyu and Yu, Zhizhou and Zhang, K. W. and Sun, L. Z. and Zhong, Jianxin},
  title = {Transport Properties of Zigzag Graphene Nanoribbons Decorated by Carboxyl Group Chains},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {44},
  pages = {21893-21898},
  url = {http://pubs.acs.org/doi/abs/10.1021/jp204888q},
  doi = {http://dx.doi.org/10.1021/jp204888q}
}
    Neha Tyagi & Anurag Srivastava Electronic Properties of AlN Nanocrystal: A First Principle Study

    [Abstract] [BibTeX]

    		 2011 AIP Conference Proceedings
    Vol. 1372(1)XVI NATIONAL SEMINAR ON FERROELECTRICS AND DIELECTRICS (NSFD-XVI), 259-262     		 DOI  
    Abstract: In the present paper, we have presented the analysis of electronic properties of 1-D AlN nanocrystal. The analysis has been made using the density functional theory based ATK-tool. The ground state total energy calculation approach of the system has been used through generalized gradient approximation (GGA) with revised Perdew-Burke-Ernzerhof (revPBE) type parameterization as exchange correlation functional. ATK has been applied to analyze the stability of Aluminium Nitride nanocrystal in its zinc blende (B3), rocksalt (B1) and CsCl (B2) type phases followed by electronic band structure and density of state computation and its analysis in comparison to its bulk crystal.
    Keywords: nanostructured materials; band structure; total energy systems; optimisation; ATK; Application
    Area: general
    BibTeX: 
    @inproceedings{Tyagi2011,
  author = {Neha Tyagi and Anurag Srivastava},
  title = {Electronic Properties of AlN Nanocrystal: A First Principle Study},
  booktitle = {XVI NATIONAL SEMINAR ON FERROELECTRICS AND DIELECTRICS (NSFD-XVI)},
  journal = {AIP Conference Proceedings},
  publisher = {AIP},
  year = {2011},
  volume = {1372},
  number = {1},
  pages = {259-262},
  doi = {http://dx.doi.org/10.1063/1.3644454}
}
    L.L. Song, X.H. Zheng, R.N. Wang, H. Hao & Z. Zeng Electron transport in metallic carbon nanotubes with multiple B and N dopants

    [Abstract] [BibTeX]

    		 2011 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 44(2), 411 - 415     		 DOI  
    Abstract: We report a first-principles investigation of the effects of multiple B and N dopants on the electron transport in metallic carbon nanotubes. Firstly, the effects of two or more B atoms which are randomly or orderly distributed are investigated. Previous study has shown that single B or N dopant gives rise to a transmission valley either below or above the Fermi level. In contrast, we find that in the cases with two B dopants, the transmission valleys can still be observed but the position and the shape of valleys are generally highly dependent on the relative positions of the dopants due to the different interference between the dopants. However, when the nanotube is symmetrically doped with more B atoms along the circumference, the transmission spectra are much more simple. The conductance plateau around the Fermi level is lowered with the increasing dopants. Secondly, the influences of B and N atoms codoping on electronic transport are studied. When one B and one N atom are doped, the effects on the equilibrium conductance of this B-N pair are always negligible. The transmission patterns can be approximately considered as a superposition of the valleys induced by the individual dopants. Especially, when the B and N atoms are nearest neighbors, the valleys induced by the individual dopants may disappear. If more B and N dopants are doped, the corresponding transmission around the Fermi level is very sensitive to how these dopants are distributed. The equilibrium conductance can be suppressed from 2.0G0 to 0.3G0 in some cases.
    Keywords: ATK; Application; nanotube; doping;
    Area: nanotubes
    BibTeX: 
    @article{Song2011,
  author = {L.L. Song and X.H. Zheng and R.N. Wang and H. Hao and Z. Zeng},
  title = {Electron transport in metallic carbon nanotubes with multiple B and N dopants},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2011},
  volume = {44},
  number = {2},
  pages = {411 - 415},
  doi = {http://dx.doi.org/10.1016/j.physe.2011.09.009}
}
    H.M. Liu, Z.Z. Zhao, N. Wang, C. Yu & J.W. Zhao Can the Transition from Tunneling to Hopping in Molecular Junctions Be Predicted by Theoretical Calculation?

    [Abstract] [BibTeX]

    		 2011 Journal of Computational Chemistry
    Vol. 32(8), 1687-1693     		 DOI  
    Abstract: The electron transport mechanism changes from tunneling to hopping as molecular length increases. To validate the theoretical simulation after the transition point and clarify influence of electronic structures on the transition, we calculated the conductance of a series of conjugated molecules by density functional theory together with the nonequilibrium Green's function. We found that the highest occupied molecular orbital energy level, transmission spectrum, and the reorganization energy are good indicators for the transition of the electron transport mechanism. The calculated resistances of short junctions (< 50 angstrom A, before the transition point) are consistent with the experimental result, following the tunneling mechanism. However, the theoretical predication failed for long molecules, indicating the limitation of the theoretical framework of elastic scattering when the electron transport mechanism changes to hopping.
    Keywords: electronic junctions; contact resistance; charge-transport; hole transport; wires; conductance; length; dependence; ATK; Application; molecular electronics; molecular junction; theoretical simulation; electron tunneling; electron hopping; reorganization energy
    Area: molecular electronics
    BibTeX: 
    @article{Liu2011e,
  author = {Liu, H. M. and Zhao, Z. Z. and Wang, N. and Yu, C. and Zhao, J. W.},
  title = {Can the Transition from Tunneling to Hopping in Molecular Junctions Be Predicted by Theoretical Calculation?},
  journal = {Journal of Computational Chemistry},
  publisher = {Wiley-blackwell},
  year = {2011},
  volume = {32},
  number = {8},
  pages = {1687--1693},
  doi = {http://dx.doi.org/10.1002/jcc.21749}
}
    Yipeng An & Zhongqin Yang Abnormal electronic transport and negative differential resistance of graphene nanoribbons with defects

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 99(19), 192102     		 DOI URL 
    Abstract: Electronic transport properties of zigzag graphene nanoribbons (GNRs) with two kinds of triangular defects are explored by using an ab-initio method. At a certain bias, the current of the GNR with an upward-triangle defect can be surprisingly larger than that of the perfect GNR due to the defect-induced symmetry breaking and more conductive channels. Dissimilarly, if the orientation of the triangle is changed rightward, the current is depressed much and shows negative differential resistance behavior. Our findings indicate that defect designs can be an efficient way to tune the electronic transport of GNR nanodevices.
    Keywords: ab initio calculations; defect states; Fermi level; graphene; nanostructured materials; negative differential resistance; NDR; ATK; Application
    Area: graphene
    BibTeX: 
    @article{An2011a,
  author = {Yipeng An and Zhongqin Yang},
  title = {Abnormal electronic transport and negative differential resistance of graphene nanoribbons with defects},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {99},
  number = {19},
  pages = {192102},
  url = {http://link.aip.org/link/?APL/99/192102/1},
  doi = {http://dx.doi.org/10.1063/1.3660228}
}
    Takahide Kubota, Masaaki Araidai, Shigemi Mizukami, Xianmin Zhang, Qinli Ma, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Masaru Tsukada & Terunobu Miyazaki Composition dependence of magnetoresistance effect and its annealing endurance in tunnel junctions having Mn-Ga electrode with high perpendicular magnetic anisotropy

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 99(19), 192509     		 DOI  
    Abstract: The composition dependence of the tunnel magnetoresistance (TMR) effect in Mn-Ga/MgO/CoFe magnetic tunnel junctions (MTJs) for Mn54Ga46, Mn62Ga38, and Mn71Ga29 (at. %) electrodes was investigated. An MTJ with a Mn62Ga38 electrode showed a maximum TMR ratio of 23% at 10 K and high annealing endurance up to 375°C. The bias voltage dependence of the TMR ratio was distinct among MTJs with different Mn-Ga compositions. Here, we discuss this dependence on the basis of the difference in the Delta1 band dispersions for Mn-Ga alloys calculated by first principles.
    Keywords: ab initio calculations; cobalt alloys; electrodes; gallium alloys; iron alloys; magnesium compounds; magnetic annealing; magnetic multilayers; manganese alloys; perpendicular magnetic anisotropy; tunnelling magnetoresistance; ATK; Application; spin; MTJ;
    Area: interfaces; spin; semi; nvm
    BibTeX: 
    @article{Kubota2011,
  author = {Takahide Kubota and Masaaki Araidai and Shigemi Mizukami and Xianmin Zhang and Qinli Ma and Hiroshi Naganuma and Mikihiko Oogane and Yasuo Ando and Masaru Tsukada and Terunobu Miyazaki},
  title = {Composition dependence of magnetoresistance effect and its annealing endurance in tunnel junctions having Mn-Ga electrode with high perpendicular magnetic anisotropy},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {99},
  number = {19},
  pages = {192509},
  doi = {http://dx.doi.org/10.1063/1.3659484}
}
    A.H. Zhang, Y.H. Wu, S.H. Ke, Y.P. Feng & C. Zhang Bandgap engineering of zigzag graphene nanoribbons by manipulating edge states via defective boundaries

    [Abstract] [BibTeX]

    		 2011 Nanotechnology
    Vol. 22(43), 435702     		 DOI  
    Abstract: One of the most severe limits of graphene nanoribbons (GNRs) in future applications is that zigzag GNRs (ZGNRs) are gapless, so cannot be used in field effect transistors (FETs), and armchair GNR (AGNR) based FETs require atomically precise control of edges and width. Using the tight-binding approach and first principles method, we derived and proved a general boundary condition for the opening of a significant bandgap in ZGNRs with defective edge structures. The proposed semiconducting ZGNRs have some interesting properties one of which is that they can be embedded and integrated in a large piece of graphene without the need to completely cut them out. We also demonstrated a new type of high-performance all-ZGNR FET. Previous proposals of graphene FETs are all based on AGNRs.
    Keywords: bottom-up; initio; devices; metals; graphene nanoribbon; defects; ATK; Application; field-effect transistor; FET;
    Area: graphene
    BibTeX: 
    @article{Zhang2011g,
  author = {Zhang, A. H. and Wu, Y. H. and Ke, S. H. and Feng, Y. P. and Zhang, C.},
  title = {Bandgap engineering of zigzag graphene nanoribbons by manipulating edge states via defective boundaries},
  journal = {Nanotechnology},
  publisher = {Iop Publishing Ltd},
  year = {2011},
  volume = {22},
  number = {43},
  pages = {435702},
  doi = {http://dx.doi.org/10.1088/0957-4484/22/43/435702}
}
    S. Choudhary & S. Qureshi Theoretical study on the effect of vacancy defect reconstruction on electron transport in Si-C nanotubes

    [Abstract] [BibTeX]

    		 2011 Modern Physics Letters B
    Vol. 25(28), 2159-2170     		 DOI  
    Abstract: We investigate the effect of vacancy defect reconstruction on electron transport properties in a (4, 0) zigzag and (5, 5) armchair silicon-carbide nanotubes (SiCNTs) by applying self consistent non-equilibrium Green's function formalism in combination with the density-functional theory to a two probe molecular junction constructed from SiCNTs. The geometry optimization results show that single vacancies and di-vacancies in SiCNTs have different reconstructions. A single vacancy when optimized, reconstructs into a 5-1DB configuration in both zigzag and armchair SiCNTs, and a di-vacancy reconstructs into a 5-8-5 configuration in zigzag and into a 5-2DB configuration in armchair SiCNTs. Analysis of frontier molecular orbitals (FMO) and transmission spectrum show that the vacancy defect increases the band gap of (4, 0) metallic SiCNT and decreases the band gap of (5, 5) semiconducting SiCNT. Bias voltage dependent current characteristic show reduction in overall current in metallic SiCNT and an increase in overall current in semiconducting SiCNT.
    Keywords: silicon-carbide nanotubes; carbon nanotubes; ab-initio; vacancies; divacancies; defects; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Choudhary2011b,
  author = {Choudhary, S. and Qureshi, S.},
  title = {Theoretical study on the effect of vacancy defect reconstruction on electron transport in Si-C nanotubes},
  journal = {Modern Physics Letters B},
  publisher = {World Scientific Publ Co Pte Ltd},
  year = {2011},
  volume = {25},
  number = {28},
  pages = {2159--2170},
  doi = {http://dx.doi.org/10.1142/S0217984911027388}
}
    Zhi-Qiang Fan, Zhen-Hua Zhang, Qiu Ming, Gui-Ping Tang & Ke-Qiu Chen First-principles study of repeated current switching in a bimolecular device

    [Abstract] [BibTeX]

    		 2012 Computational Materials Science
    Vol. 53(1), 294-297     		 DOI  
    Abstract: Using nonequilibrium Green's functions in combination with the first-principles density-functional theory, we investigate electronic transport properties of a bimolecular device consisting of two parallel placed phenalenyl molecules. When the two molecules get close enough, the currents of this bimolecular device could switch repeatedly by the mechanical strain. The deeper analysis indicates that the overlapping region size sensibly alters the coupling and charge transfer between the two parallel pi-conjugated molecules is a very important factor for this behavior.
    Keywords: nonequilibrium Green's functions; density-functional theory; bimolecular device; switching; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Fan2012,
  author = {Fan, Zhi-Qiang and Zhang, Zhen-Hua and Ming, Qiu and Tang, Gui-Ping and Chen, Ke-Qiu},
  title = {First-principles study of repeated current switching in a bimolecular device},
  journal = {Computational Materials Science},
  year = {2012},
  volume = {53},
  number = {1},
  pages = {294--297},
  doi = {http://dx.doi.org/10.1016/j.commatsci.2011.08.004}
}
    Neeraj K. Jaiswal & Pankaj Srivastava Structural stability and electronic properties of Ni-doped armchair graphene nanoribbons

    [Abstract] [BibTeX]

    		 2011 Solid State Communications
    Vol. 151(20), 1490-1495     		 DOI URL 
    Abstract: The size dependent electronic properties of armchair graphene nanoribbons (AGNR) with Ni doped atoms have been investigated using spin-unrestricted density functional theory. We predict antiferromagnetic (AFM) ground states for Ni-termination and one edge Ni-doping. The computed formation energy reveals that one edge Ni-terminated AGNR are energetically more favourable as compared to pristine ribbons. One edge substitutional doping is energetically more favourable as compared to centre doping by -1 eV whereas both edge doping is unfavourable. The bond length of substitutional Ni atoms is shorter than that of Ni adsorption in GNR, implying a stronger binding for substitutional Ni atoms. It is evident that binding energy is also affected by the coordination number of the foreign atom. The results show that Ni-interaction perturbs the electronic structure of the ribbons significantly, causing enhanced metallicity for all configurations irrespective of doping site. The band structures reveal the separation of spin up and down electronic states indicating towards the existence of spin polarized current in Ni-terminated and one edge doped ribbons. Our calculation predicts that AGNR containing Ni impurities can play an important role for the fabrication of spin filters and spintronic devices.
    Keywords: graphene nanoribbon; doping; electronic band structure; ATK; Application; spin; spin filter;
    Area: graphene; spin
    BibTeX: 
    @article{Jaiswal2011a,
  author = {Jaiswal, Neeraj K. and Srivastava, Pankaj},
  title = {Structural stability and electronic properties of Ni-doped armchair graphene nanoribbons},
  journal = {Solid State Communications},
  year = {2011},
  volume = {151},
  number = {20},
  pages = {1490--1495},
  url = {http://www.sciencedirect.com/science/article/pii/S0038109811003334},
  doi = {http://dx.doi.org/10.1016/j.ssc.2011.06.032}
}
    Y.W. Li, J.H. Yao, Z.G. Zou, J.W. Yang & S.R. Le Theoretical study of the electron transport through aromatic molecular wires with different levels of conjugation

    [Abstract] [BibTeX]

    		 2011 Computational and Theoretical Chemistry
    Vol. 976(1-3), 135-140     		 DOI URL 
    Abstract: The electron transport behaviors of three typical aromatic molecules (planar p-terphenyl, dibenzo[cd, Im]perylene, and dibenzo[bc, kl]coronene) with different levels of conjugation were studied theoretically using a combination of density functional theory and non-equilibrium Green's functions method. The results demonstrate that although the planar p-terphenyl is the least conjugated one among the three molecules, its conductance is significantly higher than those of dibenzo[cd, Im]perylene and dibenzo[bc, kl]coronene. The conductance of the three molecular wires decreases with an order of planar p-terphenyl > dibenzo[cd, Im]perylene > dibenzo[bc, kl]coronene, which is reverse to the order of the levels of conjugation of the three molecules. This unanticipated electron transport feature was analyzed from the transmission spectra and the molecular projected self-consistent Hamiltonian states of the three molecular wires under different applied bias. It is found that the orbital density at the molecule-electrode interface is the essential reason for generating this unanticipated electron transport behavior of the three aromatic molecular wires. The finding is expected to be helpful in designing and rationalization of high performance molecular wires for nanoscale applications.
    Keywords: molecular electronics; molecular conjugation; nonequilibrium Green's function; electronic transport; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Li2011e,
  author = {Li, Y.W. and Yao, J.H. and Zou, Z.G. and Yang, J.W. and Le, S.R.},
  title = {Theoretical study of the electron transport through aromatic molecular wires with different levels of conjugation},
  journal = {Computational and Theoretical Chemistry},
  year = {2011},
  volume = {976},
  number = {1-3},
  pages = {135--140},
  url = {http://www.sciencedirect.com/science/article/pii/S2210271X11004385},
  doi = {http://dx.doi.org/10.1016/j.comptc.2011.08.014}
}
    Qi Lin, Yu-Hang Chen, Jian-Bao Wu & Zong-Min Kong Effect of N-doping on band structure and transport property of zigzag graphene nanoribbons

    [Abstract] [BibTeX]

    		 2011 Acta Physica Sinica
    Vol. 60(9), 097103     		 URL 
    Abstract: The energy band structure, the transmission spectrum and the current-voltage characteristics of the N-doped zigzag graphene nanoribbons (z-GNRs) have been investigated by performing first-principles calculations. The results show the appearance of energy gap and a metal-semiconductor transition induced by N-doping of z-GNRs. With impurity concentration increasing, the current under the same bias decreases significantly, while the transmission coefficient near the Fermi surface decreases gradually. In addition, the length, the width and the N-doping position of z-GNR affect the transport property. Especially, the impurity concentration competes with the N-doping position in the influence on the transport property for narrow z-GNRs.
    Keywords: ATK; Application; graphene nanoribbons; N-doping; energy band structure; transport properties
    Area: graphene
    BibTeX: 
    @article{Lin2011a,
  author = {Lin, Qi and Chen, Yu-Hang and Wu, Jian-Bao and Kong, Zong-Min},
  title = {Effect of N-doping on band structure and transport property of zigzag graphene nanoribbons},
  journal = {Acta Physica Sinica},
  year = {2011},
  volume = {60},
  number = {9},
  pages = {097103},
  url = {http://wulixb.iphy.ac.cn/cn/ch/common/view_abstract.aspx?flag=1&file_no=w20110982}
}
    F Tavazza, L E Levine & A M Chaka Simulation approaches for studying the conductance behavior of gold nanowires during tensile deformation

    [Abstract] [BibTeX]

    		 2011 Modelling and Simulation in Materials Science and Engineering
    Vol. 19(7), 074001     		 DOI  
    Abstract: Under tensile deformation at 0 K, gold nanowires progressively thin through a series of metastable ordered structures down to a single atom chain. The conductances of these one-, two- or three-dimensional evolving self-ordered atomic structures are examined and used as test cases to explore several critical factors that must be considered when performing such calculations. These factors include the level of theory (tight binding, density functional theory, choice of basis set), the electrode geometry, and finally, the correspondence between conductance properties and the electronic band structure. Several example cases are explored.
    Keywords: ATK-SE; ATK; Application; gold nanowire; comparison; mechanical properties; deformation;
    Area: nanowires
    BibTeX: 
    @article{Tavazza2011a,
  author = {F Tavazza and L E Levine and A M Chaka},
  title = {Simulation approaches for studying the conductance behavior of gold nanowires during tensile deformation},
  journal = {Modelling and Simulation in Materials Science and Engineering},
  year = {2011},
  volume = {19},
  number = {7},
  pages = {074001},
  doi = {http://dx.doi.org/10.1088/0965-0393/19/7/074001}
}
    G.L. Zhang, H.L. Yuan, H. Zhang, Y. Shang & M. Sun Theoretical Studies on the Transport Property of Oligosilane with p-n Junction

    [Abstract] [BibTeX]

    		 2011 International Journal of Quantum Chemistry
    Vol. 111(15), 4214-4223     		 DOI  
    Abstract: The electron transport properties of a novel p-n junction nanowire caused by boron-doping and phosphorus-doping are investigated using density functional theory combined with the nonequilibrium Green's functions formalism. A satisfying rectification is observed. This is a reasonable result after the analysis of the molecular-projected self-consistent Hamitonian (MPSH) states, transmission spectra, the frontier orbitals, and the dipole moments. In contrast, the undoped chain has no rectification character. In addition, a negative differential resistance behavior is also observed at V = 1.8 similar to 2.2 V in the doped nanowire and it could be illustrated from the MPSH states and the transmission spectra.
    Keywords: electron propagator theory; molecular wires; silicon nanowires; conductance; diodes; formalism; surface; rectification; rectifier; oligomers; theoretical study; transport property; p-n junction; oligosilane; ATK; Application
    Area: nanowires
    BibTeX: 
    @article{Zhang2011e,
  author = {Zhang, G. L. and Yuan, H. L. and Zhang, H. and Shang, Y. and Sun, M.},
  title = {Theoretical Studies on the Transport Property of Oligosilane with p-n Junction},
  journal = {International Journal of Quantum Chemistry},
  publisher = {Wiley-blackwell},
  year = {2011},
  volume = {111},
  number = {15},
  pages = {4214--4223},
  doi = {http://dx.doi.org/10.1002/qua.22723}
}
    Haiying Liu, Genqin Li, Laibin Zhang, Jilai Li, Meishan Wang & Yuxiang Bu Electronic promotion effect of double proton transfer on conduction of DNA through improvement of transverse electronic communication of base pairs

    [Abstract] [BibTeX]

    		 2011 Journal of Chemical Physics
    Vol. 135(13), 134315     		 DOI  
    Abstract: The effect of double proton transfer (DPT) on charge migration of DNA was investigated by the nonequilibrium Green's function method combined with density functional theory. The results revealed that DPT not only lowers ionization potentials, but also improves the delocalization of the localized pi-orbitals at each base moiety through adjusting energy levels and spatial distributions of their molecular orbitals. Furthermore, DPT leads to both the strengthening of the second-order interactions of the Watson-Crick H-bond zones, and the promotion of the charge transfer transitions between two pairing bases in the UV absorption spectra. Electronic transport calculations indicated that DPT can improve the charge migration along the DNA duplex for specific sequences through enhancing transverse base-to-base electronic communication. This work will provide a new insight into the understanding of DNA charge conduction which can be electronically promoted or regulated by DPT.
    Keywords: bioelectric phenomena; density functional theory; dna; green's function methods; molecular biophysics; molecular configurations; ultraviolet spectra; density-functional theory; molecular-orbital methods; expanded guanine analogs; gaussian-basis sets; ab-initio; charge-transfer; excited-states; radical-cation; transport; adenine; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Liu2011c,
  author = {Haiying Liu and Genqin Li and Laibin Zhang and Jilai Li and Meishan Wang and Yuxiang Bu},
  title = {Electronic promotion effect of double proton transfer on conduction of DNA through improvement of transverse electronic communication of base pairs},
  journal = {Journal of Chemical Physics},
  publisher = {AIP},
  year = {2011},
  volume = {135},
  number = {13},
  pages = {134315},
  doi = {http://dx.doi.org/10.1063/1.3646308}
}
    Peng Zhao & Desheng Liu First-principles study of the electronic transport properties of a C131 -based molecular junction

    [Abstract] [BibTeX]

    		 2011 Solid State Communications
    Vol. 151(20), 1424 - 1427     		 DOI  
    Abstract: Using first-principles density functional theory and the non-equilibrium Green's function formalism, we have studied the electronic transport properties of the dumbbell-like fullerene dimer C131-based molecular junction. Our results show that the current-voltage curve displays an obvious negative differential resistance phenomenon in a certain bias voltage range. The negative differential resistance behavior can be understood in terms of the evolution of the transmission spectrum and the projected density of states with applied bias voltage. The present findings could be helpful for the application of the C131 molecule in the field of single molecular devices or nanometer electronics.
    Keywords: fullerene; ATK; Application; molecular junction; negative differential resistance; NDR;
    Area: fullerenes; molecular electronics
    BibTeX: 
    @article{Zhao2011d,
  author = {Peng Zhao and Desheng Liu},
  title = {First-principles study of the electronic transport properties of a C131 -based molecular junction},
  journal = {Solid State Communications},
  year = {2011},
  volume = {151},
  number = {20},
  pages = {1424 - 1427},
  doi = {http://dx.doi.org/10.1016/j.ssc.2011.07.007}
}
    Hong Seok Kang & Anup Pramanik The effect of doping on the energetics and quantum conductance in graphene nanoribbons with a metallocene adsorbate

    [BibTeX]

    		 2011 Journal of Chemical Physics
    Vol. 135(12), 124708     		 DOI  
    Keywords: adsorbed layers; adsorption; boron; bound states; doping; Fermi level; gradient methods; graphene; nanostructured materials; nitrogen; organometallic compounds; van der Waals forces; ATK; Application; ferrocene;
    Area: graphene
    BibTeX: 
    @article{Kang2011,
  author = {Hong Seok Kang and Anup Pramanik},
  title = {The effect of doping on the energetics and quantum conductance in graphene nanoribbons with a metallocene adsorbate},
  journal = {Journal of Chemical Physics},
  publisher = {AIP},
  year = {2011},
  volume = {135},
  number = {12},
  pages = {124708},
  doi = {http://dx.doi.org/10.1063/1.3643337}
}
    Jianhua Wu, Frank Hagelberg, Tandabany C. Dinadayalane, Danuta Leszczynska & Jerzy Leszczynski Do Stone-Wales Defects Alter the Magnetic and Transport Properties of Single-Walled Carbon Nanotubes?

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(45), 22232-22241     		 DOI  
    Abstract: Finite zigzag single-walled carbon nanotubes (SWCNTs) of some nanometers in length and modified by a topological defect of the Stone-Wales type were investigated by density functional theory (DFT) computation. Geometric changes of the regular hexagonal reference structures as well as alterations of their energetic, magnetic, and transport characteristics induced by the presence of the defect are recorded and discussed as a function of the tube length. SWCNT prototypes with hydrogen and fullerene hemisphere termination, and center as well as edge site defects are included in this study. The resulting four basic system types are characterized in terms of the Stone-Wales defect stabilization energy, as well as the energy gaps of the systems with and without Stone-Wales defects. While the magnetism of a zigzag SWCNT reacts sensitively to the nature and number of external adsorbates, it remains unaffected by the presence of Stone-Wales defects. However, the calculated current-voltage characteristic for a representative SWCNT with and without the defect, as well as the associated differential conductivity show a marked response to the defect for voltages exceeding about 1 V.
    Keywords: ATK; Application; nanotubes; Stone-Wales defects;
    Area: nanotubes
    BibTeX: 
    @article{Wu2011b,
  author = {Wu, Jianhua and Hagelberg, Frank and Dinadayalane, Tandabany C. and Leszczynska, Danuta and Leszczynski, Jerzy},
  title = {Do Stone-Wales Defects Alter the Magnetic and Transport Properties of Single-Walled Carbon Nanotubes?},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {45},
  pages = {22232-22241},
  doi = {http://dx.doi.org/10.1021/jp207510n}
}
    J.H. Yao, Y.W. Li, Z.G. Zou, J.W. Yang & Z.L. Yin First principles study of the electron transport through cis-polyacetylene based molecular wires

    [Abstract] [BibTeX]

    		 2011 Physica B: Condensed Matter
    Vol. 406(20), 3969-3974     		 DOI  
    Abstract: The electron transport properties of cis-polyacetylene and cis-polyacetylene based molecular wires (oligo(cyclopentadiene), oligo(pyrrole), and oligo(furan)) have been studied theoretically using a combination of density-functional theory and non-equilibrium Green's functions method. The results demonstrate that the introduction of bridging group X (X=CH(2), NH, and O) in cis-polyacetylene has a profound effect on the electron transport behavior of the molecules. The conductance of the four molecular wires decreases in the order of polyacetylene > oligo(cyclopentadiene) > oligo(furan) > oligo(pyrrole). In particular, the conductances of oligo(furan) and oligo(pyrrole) are much lower than those of polyacetylene and oligo(cyclopentadiene). The mechanism of this difference of electron transport properties of these four molecular systems is analyzed in terms of their geometric structures, electronic structures, transmission spectra, and spatial distribution of frontier orbitals. It is found that the energy levels of frontier molecular orbitals and the evolution of spatial distribution of frontier molecular orbitals with the applied bias are the essential reason for generating this difference of electron transport behaviors of the four molecular systems.
    Keywords: junction conductance; band-gaps; copolymers; dependence; resistance; behavior; devices; state; field; ATK; Application; molecular electronics; molecular wires; non-equilibrium Green's function; electron transport
    Area: molecular electronics
    BibTeX: 
    @article{Yao2011,
  author = {Yao, J. H. and Li, Y. W. and Zou, Z. G. and Yang, J. W. and Yin, Z. L.},
  title = {First principles study of the electron transport through cis-polyacetylene based molecular wires},
  journal = {Physica B: Condensed Matter},
  publisher = {Elsevier Science Bv},
  year = {2011},
  volume = {406},
  number = {20},
  pages = {3969--3974},
  doi = {http://dx.doi.org/10.1016/j.physb.2011.07.040}
}
    S.D. Yuan, S.Y. Wang, Q.B. Mei, Q.D. Ling, L.H. Wang & W. Huang First-Principles Study of Rectification in Bis-2-(5-ethynylthienyl)ethyne Molecular Junctions

    [Abstract] [BibTeX]

    		 2011 Journal of Physical Chemistry A
    Vol. 115(32), 9033-9042     		 DOI  
    Abstract: Using density functional theory (DFT) combined with the first-principles nonequilibrium Green's function (NEGF), we investigated the electron-transport properties and rectifying behaviors of several molecular junctions based on the bis-2-(5-ethynylthienyl)ethyne (BETE) molecule. To examine the roles of different rectification factors, asymmetric electrode molecule contacts and donor-acceptor substituent groups were introduced into the BETE-based molecular junction. The asymmetric current-voltage characteristics were obtained for the molecular junctions containing asymmetric contacts and donor-acceptor groups. In our models, the computed rectification ratios show that the mode of electrode-molecule contacts plays a crucial role in rectification and that the rectifying effect is not enhanced significantly by introducing the additional donor-acceptor components for the molecular rectifier with asymmetric electrode molecule contacts. The current-voltage characteristics and rectifying behaviors are discussed in terms of transmission spectra, molecular projected self-consistent Hamiltonian (MPSH) states, and energy levels of MPSH states.
    Keywords: self-assembled monolayers; electronic transport; anchoring group; conductance; density; rectifiers; devices; diodes; substituents; contacts; ATK; Application; molecular electronics
    Area: molecular electronics
    BibTeX: 
    @article{Yuan2011a,
  author = {Yuan, S. D. and Wang, S. Y. and Mei, Q. B. and Ling, Q. D. and Wang, L. H. and Huang, W.},
  title = {First-Principles Study of Rectification in Bis-2-(5-ethynylthienyl)ethyne Molecular Junctions},
  journal = {Journal of Physical Chemistry A},
  publisher = {Amer Chemical Soc},
  year = {2011},
  volume = {115},
  number = {32},
  pages = {9033--9042},
  doi = {http://dx.doi.org/10.1021/jp204161z}
}
    Anirban Bandyopadhyay & Somobrata Acharya A 16-bit parallel processing in a molecular assembly

    [Abstract] [BibTeX]

    		 2008 Proceedings of the National Academy of Sciences
    Vol. 105(10), 3668-3672     		 DOI  
    Abstract: A machine assembly consisting of 17 identical molecules of 2,3,5,6-tetramethyl-1-4-benzoquinone (DRQ) executes 16 instructions at a time. A single DRQ is positioned at the center of a circular ring formed by 16 other DRQs, controlling their operation in parallel through hydrogen-bond channels. Each molecule is a logic machine and generates four instructions by rotating its alkyl groups. A single instruction executed by a scanning tunneling microscope tip on the central molecule can change decisions of 16 machines simultaneously, in four billion (4^16) ways. This parallel communication represents a significant conceptual advance relative to today's fastest processors, which execute only one instruction at a time.
    Keywords: ATK; Application; molecular switch;
    Area: molecular electronics
    BibTeX: 
    @article{Bandyopadhyay2008,
  author = {Bandyopadhyay, Anirban and Acharya, Somobrata},
  title = {A 16-bit parallel processing in a molecular assembly},
  journal = {Proceedings of the National Academy of Sciences},
  year = {2008},
  volume = {105},
  number = {10},
  pages = {3668--3672},
  doi = {http://dx.doi.org/10.1073/pnas.0703105105}
}
    Anirban Bandyopadhyay, Ranjit Pati, Satyajit Sahu, Ferdinand Peper & Daisuke Fujita Massively parallel computing on an organic molecular layer

    [Abstract] [BibTeX]

    		 2010 Nature Physics
    Vol. 6(5), 369-375     		 DOI  
    Abstract: Modern computers operate at enormous speeds - capable of executing in excess of 10^13 instructions per second - but their sequential approach to processing, by which logical operations are performed one after another, has remained unchanged since the 1950s. In contrast, although individual neurons of the human brain fire at around just 10^3 times per second, the simultaneous collective action of millions of neurons enables them to complete certain tasks more efficiently than even the fastest supercomputer. Here we demonstrate an assembly of molecular switches that simultaneously interact to perform a variety of computational tasks including conventional digital logic, calculating Voronoi diagrams, and simulating natural phenomena such as heat diffusion and cancer growth. As well as representing a conceptual shift from serial-processing with static architectures, our parallel, dynamically reconfigurable approach could provide a means to solve otherwise intractable computational problems.
    Keywords: ATK; Application; molecular switch;
    Area: molecular electronics
    BibTeX: 
    @article{Bandyopadhyay2010,
  author = {Bandyopadhyay, Anirban and Pati, Ranjit and Sahu, Satyajit and Peper, Ferdinand and Fujita, Daisuke},
  title = {Massively parallel computing on an organic molecular layer},
  journal = {Nature Physics},
  publisher = {Nature Publishing Group},
  year = {2010},
  volume = {6},
  number = {5},
  pages = {369--375},
  doi = {http://dx.doi.org/10.1038/nphys1636}
}
    Mohammad Khazaei, Yunye Liang, Mohammad Saeed Bahramy, Fabio Pichierri, Keivan Esfarjani & Yoshiyuki Kawazoe High-pressure phases of hydrogen cyanide: formation of hydrogenated carbon nitride polymers and layers and their electronic properties

    [Abstract] [BibTeX]

    		 2011 Journal of Physics: Condensed Matter
    Vol. 23(40), 405403     		 DOI  
    Abstract: We have performed a set of first-principles simulations to consider the possible phase transitions in molecular crystals of HCN under high pressure. Our calculations reveal several transition paths from the orthorhombic phase to tetragonal and then to triclinic phases. The transitions from the orthorhombic to the tetragonal phases are of the second order, whereas those from the tetragonal to the triclinic phases turn out to be of the first-order type and characterized by an abrupt decrease in volume. Our calculations show that, by adjustment of the temperature and pressure of the HCN molecular crystal, novel layered and polymeric crystals with insulating, semiconducting or metallic properties can be found. Based on our simulation results, two different crystal formation mechanisms are deduced. The stabilities of the predicted structures at ambient pressure are further assessed by performing phonon or MD simulations. In addition, the electron transport properties of the predicted polymers are obtained using the non-equilibrium Green's function technique combined with density functional theory. The results show that the polymers have metallic-like I-V characteristics.
    Keywords: molecular electronics; molecular crystal; phase transition; density-functional theory; computer experiments; (hcn)(n) clusters; classical fluids; solid hcn; crystals; energy; transformation; computations; spectroscopy; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Khazaei2011,
  author = {Mohammad Khazaei and Yunye Liang and Mohammad Saeed Bahramy and Fabio Pichierri and Keivan Esfarjani and Yoshiyuki Kawazoe},
  title = {High-pressure phases of hydrogen cyanide: formation of hydrogenated carbon nitride polymers and layers and their electronic properties},
  journal = {Journal of Physics: Condensed Matter},
  year = {2011},
  volume = {23},
  number = {40},
  pages = {405403},
  doi = {http://dx.doi.org/10.1088/0953-8984/23/40/405403}
}
    Xiaojian Tan, Huijun Liu, Yanwei Wen, Hongyan Lv, Lu Pan, Jing Shi & Xinfeng Tang Thermoelectric Properties of Ultra-Small Single-Wall Carbon Nanotubes

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115, 21996     		 DOI  
    Abstract: The electronic transports of three kinds of ultra-small single-wall carbon nanotubes are studied by using nonequilibrium Green's function method. It is found that the transmission function displays a clear stepwise structure that gives the number of electron channels. The calculated power factor (S^2G ) of these nanotubes can be optimized to much higher values in a wide temperature range. Using nonequilibrium molecule dynamics simulations, the lattice thermal conductance of these nanotubes are predicated with quantum correction. Our calculations indicate that the (4,2) tube have relatively higher room temperature figure of merit (ZT value) compared with those of the (5,0) and (3,3) tubes. Moreover, the thermoelectric performance of these nanotubes can be greatly enhanced by surface design, formation of bundles, and increasing the tube length, etc which significantly reduce the phonon and/or electron derived thermal conductance.
    Keywords: nanotubes; thermoelectricity; figure of merit; ZT; ATK; Application
    Area: nanotubes; thermo
    BibTeX: 
    @article{Tan2011,
  author = {Tan, Xiaojian and Liu, Huijun and Wen, Yanwei and Lv, Hongyan and Pan, Lu and Shi, Jing and Tang, Xinfeng},
  title = {Thermoelectric Properties of Ultra-Small Single-Wall Carbon Nanotubes},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  pages = {21996},
  doi = {http://dx.doi.org/10.1021/jp205333m}
}
    Minggang Zeng, Yuanping Feng & Gengchiau Liang Thermally induced currents in graphene-based heterostructure

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 99(12), 123114     		 DOI  
    Abstract: We investigate thermally induced currents in a zigzag graphene nanoribbon (ZGNR) heterostructure, consisting of hydrogen-terminated ZGNR (ZGNR-H) and oxygen-terminated ZGNR (ZGNR-O), under different electronic and magnetic states. Compared to a pure ZGNR-H system, the heterostructure displays a considerably larger thermally induced current due to its asymmetric transmission spectrum. Moreover, the magnetized ZGNR-H/ZGNR-O shows spin filter and magnetoresistance effects, suggesting potential applications of the ZGNR-H/ZGNR-O heterostructures in thermoelectric and spintronics devices.
    Keywords: graphene nanoribbon; heterostructure; magnetoelectronics; magnetoresistance; nanostructured materials; thermal conductivity; ATK; Application; field-effect transistor; spin filtering; spintronics; thermoelectricity
    Area: graphene; spin; thermo
    BibTeX: 
    @article{Zeng2011f,
  author = {Minggang Zeng and Yuanping Feng and Gengchiau Liang},
  title = {Thermally induced currents in graphene-based heterostructure},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {99},
  number = {12},
  pages = {123114},
  doi = {http://dx.doi.org/10.1063/1.3641478}
}
    Z.Q. Fan, Z.H. Zhang, M. Qiu & G.P. Tang Rectifying performance and reversible conductance switching of single-polyaniline devices

    [Abstract] [BibTeX]

    		 2011 Physics Letters A
    Vol. 375(37), 3314-3318     		 DOI  
    Abstract: By applying nonequilibrium Green's functions in combination with the density-functional theory, we investigate the transport properties of single-polyaniline molecular devices. The results show that these devices can perform a reversible switching behavior by oxidation/reduction, which agrees well with the experimental results. In addition, a rectifying performance is only found in the device on emeraldine base. Detailed analyses of the charge transfer and the transmission spectra of the devices reveal the mechanism of these behaviors.
    Keywords: transport properties; molecular electronics; ATK; Application; conductance switching;
    Area: molecular electronics
    BibTeX: 
    @article{Fan2011a,
  author = {Fan, Z. Q. and Zhang, Z. H. and Qiu, M. and Tang, G. P.},
  title = {Rectifying performance and reversible conductance switching of single-polyaniline devices},
  journal = {Physics Letters A},
  publisher = {Elsevier Science Bv},
  year = {2011},
  volume = {375},
  number = {37},
  pages = {3314--3318},
  doi = {http://dx.doi.org/10.1016/j.physleta.2011.07.023}
}
    Changfeng Fang, Bin Cui, Yuqing Xu, Guomin Ji, Desheng Liu & Shijie Xie Electronic transport properties of carbon chains between Au and Ag electrodes: A first-principles study

    [Abstract] [BibTeX]

    		 2011 Physics Letters A
    Vol. 375(41), 3618-3623     		 DOI  
    Abstract: We report first-principles calculations of the current-voltage characteristic and the conductance of carbon-based molecular wires with different length capped with sulfur ends between two metallic electrodes made of different metals. The optimized molecular structure of carbon chain in the junction is presented on the structure of polyyne. The conductance of the polyyne wires shows oscillatory behavior depending on the number of carbon atoms (triple bonds). Current rectification is found and rectification direction presents inversion with the odd and even number of carbon atoms.
    Keywords: Electronic transport; Rectification; Asymmetric electrode; Non-equilibrium Green's function; molecular electronics; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Fang2011a,
  author = {Fang, Changfeng and Cui, Bin and Xu, Yuqing and Ji, Guomin and Liu, Desheng and Xie, Shijie},
  title = {Electronic transport properties of carbon chains between Au and Ag electrodes: A first-principles study},
  journal = {Physics Letters A},
  year = {2011},
  volume = {375},
  number = {41},
  pages = {3618--3623},
  doi = {http://dx.doi.org/10.1016/j.physleta.2011.08.032}
}
    J. Puigmarti-Luis, A. Minoia, S.B. Lei, V. Geskin, B. Li, R. Lazzaroni, S. De Feyter & D.B. Amabilino Self-assembly of supramolecular wires and cross-junctions and efficient electron tunnelling across them

    [Abstract] [BibTeX]

    		 2011 Chemical Science
    Vol. 2(10), 1945-1951     		 DOI  
    Abstract: The self-assembly of molecules incorporating pi-electron rich units into supramolecular wires is shown by scanning tunnelling microscopy (STM) at a graphite-liquid interface. Hydrogen bonds between the side chains of these molecules ensure a face-to-face contact between the functional moieties, which would otherwise lie flat on the surface if the amide groups affording this effect were absent. The organisation in the wires also depends critically on the constitution of the molecule: The cis and trans isomers show ordered and disordered spacing between wires, respectively. The supramolecular wires formed by the cis isomer form crossed architectures, with multilayers of the linear structures being formed. Study of the junction points between the fibres by scanning tunnelling spectroscopy shows that tunnelling electrons are transported efficiently, practically with the same probability as through a single wire. Molecular modelling is used to determine how the pi-electron rich units within two crossing wires organise at the crossing. Based on those structural data, the electron tunnelling probability between tip and substrate is then calculated; it shows that electron transmission can indeed take place at the crossing. This result implies that supramolecular fibres can be used as wires in order to build integrated circuits by bottom-up construction from the molecule scale.
    Keywords: liquid-solid interface; tetrathiafulvalene derivatives; organic-molecules; building-blocks; fibers; transport; surfaces; devices; nanostructures; microscopy; ATK; Application; experimental comparison
    Area: molecular electronics
    BibTeX: 
    @article{PuigmartiLuis2011,
  author = {Puigmarti-Luis, J. and Minoia, A. and Lei, S. B. and Geskin, V. and Li, B. and Lazzaroni, R. and De Feyter, S. and Amabilino, D. B.},
  title = {Self-assembly of supramolecular wires and cross-junctions and efficient electron tunnelling across them},
  journal = {Chemical Science},
  publisher = {Royal Soc Chemistry},
  year = {2011},
  volume = {2},
  number = {10},
  pages = {1945--1951},
  doi = {http://dx.doi.org/10.1039/c1sc00330e}
}
    F. Tavazza, D.T. Smith, L.E. Levine, J.R. Pratt & A.M. Chaka Electron Transport in Gold Nanowires: Stable 1-, 2- and 3-Dimensional Atomic Structures and Noninteger Conduction States

    [Abstract] [BibTeX]

    		 2011 Physical Review Letters
    Vol. 107(12), 126802-     		 DOI  
    Abstract: Experimental conductivity measurements made during highly stable tensile deformation of Au nanowires show a rich variety of behaviors, including noninteger quantum conductance plateaus, transitions, and slopes. Using tight binding conductance calculations on simulated nanowires previously deformed using density functional theory, we demonstrate that all of these phenomena arise from structural transitions between deeply metastable ordered atomic configurations that self-organize during tensile deformation.
    Keywords: gold nanowire; ATK; ATK-SE; Application; experimental comparison; quantum conductance; strain
    Area: nanowires
    BibTeX: 
    @article{Tavazza2011,
  author = {Tavazza, F. and Smith, D. T. and Levine, L. E. and Pratt, J. R. and Chaka, A. M.},
  title = {Electron Transport in Gold Nanowires: Stable 1-, 2- and 3-Dimensional Atomic Structures and Noninteger Conduction States},
  journal = {Physical Review Letters},
  publisher = {American Physical Society},
  year = {2011},
  volume = {107},
  number = {12},
  pages = {126802--},
  doi = {http://dx.doi.org/10.1103/PhysRevLett.107.126802}
}
    Cai-Juan Xia, De-Sheng Liu & Ying-Tang Zhang Electronic Transport Properties of a Naphthopyran-Based Optical Molecular Switch: an ab initio Study

    [Abstract] [BibTeX]

    		 2011 Chinese Physics Letters
    Vol. 28(9), 093102     		 DOI  
    Abstract: The electronic transport properties of a naphthopyran-based molecular optical switch are investigated by using the nonequilibrium Green's function formalism combined with first-principles density functional theory. The molecule that comprises the switch can convert between its open and closed forms upon photoexcitation. Theoretical results show that the current through the open form is significantly larger than that through the closed form, which is different from other optical switches based on ring-opening reactions of the molecular bridge. The maximum on-off ratio (about 90) can be obtained at 1.4 V. The physical origin of the switching behavior is interpreted based on the spatial distributions of molecular orbitals and the HOMO-LUMO gap. Our result shows that the naphthopyran-based molecule is a good candidate for optical molecular switches and will be useful in the near future.
    Keywords: ATK; Application; molecular optical switch;
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011h,
  author = {Xia, Cai-Juan and Liu, De-Sheng and Zhang, Ying-Tang},
  title = {Electronic Transport Properties of a Naphthopyran-Based Optical Molecular Switch: an ab initio Study},
  journal = {Chinese Physics Letters},
  year = {2011},
  volume = {28},
  number = {9},
  pages = {093102},
  doi = {http://dx.doi.org/10.1088/0256-307X/28/9/093102}
}
    J. Zeng, K.Q. Chen, J. He, X.J. Zhang & W.P. Hu Rectifying and successive switch behaviors induced by weak intermolecular interaction

    [Abstract] [BibTeX]

    		 2011 Organic Electronics
    Vol. 12(10), 1606-1611     		 DOI  
    Abstract: By applying nonequilibrium Green's functions in combination with density-function theory, we investigate the effect of the weak intermolecular interaction on electronic transport properties in a bilayer graphene nanoribbon device. The results show that a successive switch behavior can be realized by adjusting the weak pi-pi interaction between two graphene nanoribbon molecules. Moreover, rectifying behavior can be observed in such systems. The mechanisms for these phenomena are suggested.
    Keywords: electronic transport; graphene; junctions; conductance; electronic transport in nanoscale materials and structures; switch behaviors; current rectification; weak intermolecular interaction; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Zeng2011e,
  author = {Zeng, J. and Chen, K. Q. and He, J. and Zhang, X. J. and Hu, W. P.},
  title = {Rectifying and successive switch behaviors induced by weak intermolecular interaction},
  journal = {Organic Electronics},
  publisher = {Elsevier Science Bv},
  year = {2011},
  volume = {12},
  number = {10},
  pages = {1606--1611},
  doi = {http://dx.doi.org/10.1016/j.orgel.2011.06.010}
}
    X.J. Zhang, K.Q. Chen, L.M. Tang & M.Q. Long Electronic transport properties on V-shaped-notched zigzag graphene nanoribbons junctions

    [Abstract] [BibTeX]

    		 2011 Physics Letters A
    Vol. 375(37), 3319-3324     		 DOI  
    Abstract: Using nonequilibrium Green's functions in combination with the density functional theory, the spin-dependent electronic transport properties on V-shaped notched zigzag-edged graphene nanoribbons junctions have been calculated. The results show that the electronic transport properties are strongly depending on the type of notch and the symmetry of ribbon. The spin-filter phenomenon and negative differential resistance behaviors can be observed. A physical analysis of these results is given.
    Keywords: graphene nanoribbons; v-shaped notch; first-principles; electronic transport properties; spin filter; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Zhang2011d,
  author = {Zhang, X. J. and Chen, K. Q. and Tang, L. M. and Long, M. Q.},
  title = {Electronic transport properties on V-shaped-notched zigzag graphene nanoribbons junctions},
  journal = {Physics Letters A},
  publisher = {Elsevier Science Bv},
  year = {2011},
  volume = {375},
  number = {37},
  pages = {3319--3324},
  doi = {http://dx.doi.org/10.1016/j.physleta.2011.07.029}
}
    K.G. Zhou, Y.H. Zhang, L.J. Wang, K.F. Xie, Y.Q. Xiong, H.L. Zhang & C.W. Wang Can azulene-like molecules function as substitution-free molecular rectifiers?

    [Abstract] [BibTeX]

    		 2011 Physical Chemistry Chemical Physics
    Vol. 13(35), 15882-15890     		 DOI  
    Abstract: The feasibility of employing azulene-like molecules as a new type of high performance substitution-free molecular rectifier has been explored using NEGF-DFT calculation. The electronic transport behaviors of metal-molecule-metal junctions consisting of various azulene-like dithiol molecules are investigated, which reveals that the azulene-like molecules exhibit high conductance and bias-dependent rectification effects. Among all the substitution-free azulene-like structures, cyclohepta[b]cyclopenta[g]naphthalene exhibits the highest rectification ratio, revealing that the all fused aromatic ring structure and an appropriate separation between the pentagon and heptagon rings are essential for achieving both high conductance and high rectification ratio. The rectification ratio can be increased by substituting the pentagon ring with electron withdrawing group and/or the heptagon ring with electron donating groups. Further increase of the rectification ratio may also be obtained by lithium adsorption on the pentagon ring. This work reveals that azulene-like molecules may be used as a new class of highly conductive unimolecular rectifiers.
    Keywords: quantum transport-properties; self-assembled monolayers; ab-initio; gold electrodes; rectification; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Zhou2011a,
  author = {Zhou, K. G. and Zhang, Y. H. and Wang, L. J. and Xie, K. F. and Xiong, Y. Q. and Zhang, H. L. and Wang, C. W.},
  title = {Can azulene-like molecules function as substitution-free molecular rectifiers?},
  journal = {Physical Chemistry Chemical Physics},
  publisher = {Royal Soc Chemistry},
  year = {2011},
  volume = {13},
  number = {35},
  pages = {15882--15890},
  doi = {http://dx.doi.org/10.1039/c0cp02693j}
}
    I.B.M. Dason, V.R. Kumar & A.A. Kirubaraj Realization of Magnetic RAM using Magnetic Tunneling Junction in atomic level

    [Abstract] [BibTeX]

    		 2011
    Vol. 4Electronics Computer Technology (ICECT), 2011 3rd International Conference on, 397 -401     		 DOI  
    Abstract: Magnetic RAM (MRAM) is the non-volatile memory device with excellent endurance. Magnetic Tunneling Junction (MTJ) is the basic building block of the MRAM which is used to store information extracting the two-valued resistance property. With the discovery of Giant Magneto Resistance effect (GMR) and Tunnel Magneto Resistance effect (TMR) phenomenon in the magnetic multilayer of MTJ, the difference between the two resistances is distinct. Writing in MTJ can be carried with superior speed, low power using Spin Transfer Torque (STT) writing technique. The parallel and anti-parallel configurations of the MTJ can be carried out by manipulating the spin of the electrons of the magnetic multilayer. In this paper, we have modelled the Fe-MgO-Fe MTJ in atomic level using the software Atomistix ToolKit (ATK) Virtual NanoLab (VNL) 2008.10. We have analysed the V-I characteristics of the MTJ for the various bias voltages and have obtained the resistance of 5.2 M Ohm and 55.7 M Ohm for the parallel and anti-parallel configurations respectively. This difference in the two resistances holds good to differentiate the data "0" or "1" stored in the MTJ. The TMR thus calculated is around 950%. Higher the TMR ratio lower is the Resistance Area (RA) product.
    Keywords: Atomistix ToolKit software; Virtual NanoLab 2008.10; atomic level; giant magneto resistance effect; information extraction; magnetic RAM; magnetic multilayer; magnetic tunneling junction; nonvolatile memory device; resistance area product; spin transfer torque writing technique; tunnel magneto resistance effect; two-valued resistance property; MRAM devices; giant magnetoresistance; information retrieval; magnetic multilayers; tunnelling magnetoresistance; virtual instrumentation; MTJ; spin; ATK; Application
    Area: interfaces; spin; semi; nvm
    BibTeX: 
    @inproceedings{5941929,
  author = {Dason, I.B.M. and Kumar, V.R. and Kirubaraj, A.A.},
  title = {Realization of Magnetic RAM using Magnetic Tunneling Junction in atomic level},
  booktitle = {Electronics Computer Technology (ICECT), 2011 3rd International Conference on},
  year = {2011},
  volume = {4},
  pages = {397 -401},
  doi = {http://dx.doi.org/10.1109/ICECTECH.2011.5941929}
}
    H. Medina, Y.C. Lin, D. Obergfell & P.W. Chiu Tuning of Charge Densities in Graphene by Molecule Doping

    [Abstract] [BibTeX]

    		 2011 Advanced Functional Materials
    Vol. 21(14), 2687-2692     		 DOI  
    Abstract: The tuning of carrier concentrations in graphene is at the heart of graphene-based nanoelectronic and optoelectronic applications. Molecular doping, that is, taking charges from the adsorbed molecules, shows promise as a means by which to change carrier density in graphene while retaining relative high mobility. However, poor control over doping concentrations is a major obstacle to practical applications. Here, we show that lattice disorders induced by plasma exposure can be used as anchor groups. These groups serve as centers of molecule adsorption and facilitate orbital overlap between graphene and adsorbates (melamine), thus allowing for selective and tunable doping. The carrier concentration revealed by Raman shift can be progressively adjusted up to 1.4 x 10(13) cm(-2), depending on the coverage of melamine molecules and doping temperature. The electronic band structures of the graphene melamine complex were calculated using density functional theory for adsorption over ideal graphene and over non-ideal graphene with Stone-Wales (5-7-7-5) defects. It is shown that charge transfer for adsorption on ideal graphene is negligible, while adsorption on graphene with Stone-Wales defects results in weak hole doping, which is consistent with the progressive increase of carrier density with increasing melamine coverage.
    Keywords: field-effect transistors; raman-scattering; defects; films; gas; graphene; doping; experimental comparison; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Medina2011,
  author = {Medina, H. and Lin, Y. C. and Obergfell, D. and Chiu, P. W.},
  title = {Tuning of Charge Densities in Graphene by Molecule Doping},
  journal = {Advanced Functional Materials},
  publisher = {Wiley-blackwell},
  year = {2011},
  volume = {21},
  number = {14},
  pages = {2687--2692},
  doi = {http://dx.doi.org/10.1002/adfm.201100401}
}
    Anurag Srivastava, Neha Tyagi & R.K. Singh First Principle Study of Structural and Electronic Properties of Silicon Nanowires

    [Abstract] [BibTeX]

    		 2011 Journal of Computational and Theoretical Nanoscience
    Vol. 8(8), 1418-1423     		 DOI  
    Abstract: Ab-initio self-consistent study of Silicon nanostructures have been performed in various atomic configurations using atomistix tool. Atomic geometries of Silicon nanowires with the lowest energy have been analysed to confirm their stability. Out of the six atomic geometries of Silicon nanowire taken into consideration (linear, zigzag, ladder, square, triangular and dumbbell), the two-atom zigzag shaped geometry with the lowest total energy and highest binding energy has been confirmed as the most stable structure. The study has been made using GGA exchange correlation with revised Perdew Burke and Ernzerhoff type parameterization. The calculated lattice parameter of bulk silicon is in good agreement with its experimental counterpart. The electronic band structures, density of states and bulk modulus for different atomic geometries of Si nanowires have also been analysed.
    Keywords: silicon nanowires; stability; electronic properties; bulk modulus; ab initio; ATK; Application
    Area: nanowires
    BibTeX: 
    @article{Srivastava2011a,
  author = {Srivastava, Anurag and Tyagi, Neha and Singh, R.K.},
  title = {First Principle Study of Structural and Electronic Properties of Silicon Nanowires},
  journal = {Journal of Computational and Theoretical Nanoscience},
  year = {2011},
  volume = {8},
  number = {8},
  pages = {1418--1423},
  doi = {http://dx.doi.org/10.1166/jctn.2011.1830}
}
    C.Y. Xu, L.Z. Li, H. Li, R. Qin, J.X. Zheng, G.F. Luo, Q.H. Liu, X. Yan, L.L. Yu, J. Lu & Z.X. Gao Sign-changeable spin-filter efficiency and giant magnetoresistance in seamless graphene nanoribbon junctions

    [Abstract] [BibTeX]

    		 2011 Computational Materials Science
    Vol. 50(10), 2886-2890     		 DOI  
    Abstract: Sign-changeable spin-filter efficiency is predicted in both the ferromagnetic and antiferromagnetic configurations of a zigzag graphene nanoribbon bridging two half-planar graphene electrodes from ab initio quantum transport calculations. By changing edge spin-polarization configuration, we obtain giant room-temperature magnetoresistance, which is one order of magnitude larger than the maximum experimental results.
    Keywords: graphene nanoribbon; spin-filter efficiency; magnetoresistance; quantum transport calculation; room-temperature; transport; devices; graphite; gas; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Xu2011a,
  author = {Xu, C. Y. and Li, L. Z. and Li, H. and Qin, R. and Zheng, J. X. and Luo, G. F. and Liu, Q. H. and Yan, X. and Yu, L. L. and Lu, J. and Gao, Z. X.},
  title = {Sign-changeable spin-filter efficiency and giant magnetoresistance in seamless graphene nanoribbon junctions},
  journal = {Computational Materials Science},
  publisher = {Elsevier Science Bv},
  year = {2011},
  volume = {50},
  number = {10},
  pages = {2886--2890},
  doi = {http://dx.doi.org/10.1016/j.commatsci.2011.05.004}
}
    V.M.K. Bagci & C.C. Kaun Recognizing nucleotides by cross-tunneling currents for DNA sequencing

    [Abstract] [BibTeX]

    		 2011 Physical Review E
    Vol. 84(1), 011917     		 DOI  
    Abstract: Using first-principles calculations, we study electron transport through nucleotides inside a rectangular nanogap formed by two pairs of gold electrodes which are perpendicular and parallel to the nucleobase plane. We propose that this setup will enhance the nucleotide selectivity of tunneling signals to a great extent. Information from three electrical probing processes offers full nucleotide recognition, which survives the noise from neighboring nucleotides and configuration fluctuations.
    Keywords: transverse electronic transport; nanopore; molecule; nucleotides; DNA; bases; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Bagci2011,
  author = {Bagci, V. M. K. and Kaun, C. C.},
  title = {Recognizing nucleotides by cross-tunneling currents for DNA sequencing},
  journal = {Physical Review E},
  publisher = {Amer Physical Soc},
  year = {2011},
  volume = {84},
  number = {1},
  pages = {011917},
  doi = {http://dx.doi.org/10.1103/PhysRevE.84.011917}
}
    Kamal K. Saha, Marija Drndic & Branislav K. Nikolic DNA Base-Specific Modulation of Microampere Transverse Edge Currents through a Metallic Graphene Nanoribbon with a Nanopore

    [Abstract] [BibTeX]

    		 2012 Nano Letters
    Vol. 12(1), 50-55arXiv:1108.3801v1 [cond-mat.mes-hall]     		 DOI  
    Abstract: We study two-terminal devices for DNA sequencing that consist of a metallic graphene nanoribbon with zigzag edges (ZGNR) and a nanopore in its interior through which the DNA molecule is translocated. Using the nonequilibrium Green functions combined with density functional theory, we demonstrate that each of the four DNA nucleobases inserted into the nanopore, whose edge carbon atoms are passivated by either hydrogen or nitrogen, will lead to a unique change in the device conductance. Unlike other recent biosensors based on transverse electronic transport through translocated DNA, which utilize small (of the order of pA) tunneling current across a nanogap or a nanopore yielding a poor signal-to-noise ratio, our device concept relies on the fact that in ZGNRs local current density is peaked around the edges so that drilling a nanopore away from the edges will not diminish the conductance. Inserting a nucleobase into the nanopore affects the charge density in the surrounding area, thereby modulating edge conduction currents whose magnitude is of the order of microampere at bias voltage 0.1 V. The proposed biosensors are not limited to ZGNRs and they could be realized with other nanowires supporting transverse edge currents, such as chiral GNRs or wires made of two-dimensional topological insulators.
    Keywords: ATK; Application; DNA sequencing; graphene nanoribbons; nanopore; first-principles quantum transport; NEGF-DFT
    Area: graphene
    BibTeX: 
    @article{Saha2012,
  author = {Saha, Kamal K. and Drndic, Marija and Nikolic, Branislav K.},
  title = {DNA Base-Specific Modulation of Microampere Transverse Edge Currents through a Metallic Graphene Nanoribbon with a Nanopore},
  journal = {Nano Letters},
  year = {2012},
  volume = {12},
  number = {1},
  pages = {50--55},
  doi = {http://dx.doi.org/10.1021/nl202870y}
}
    Neeraj K. Jaiswal & Pankaj Srivastava First principles calculations of armchair graphene nanoribbons interacting with Cu atoms

    [Abstract] [BibTeX]

    		 2011 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 44(1), 75-79     		 DOI  
    Abstract: We have investigated the electronic properties of bare, H-terminated, Cu-terminated and Cu-doped armchair graphene nanoribbons (AGNRs) using ab-initio approach. We found that H-termination enhances the stability and band gap whereas H extraction introduces dangling bands and lowers the band gap making bare ribbons indirect band gap semiconductors. The calculations revealed that strong hybridization between Cu atoms and AGNRs, lessen the band gap for Cu-terminated ribbons and gives rise to metallicity in Cu-doped AGNRs irrespective of their widths. Formation energy of considered ribbons yield that H-terminated AGNRs with lowest formation energy are most energetically favored, next are one edge Cu-terminated ribbons followed by bare ones whereas both edges Cu-doped ribbons are least energetically plausible. We predict that presence of Cu atoms in GNRs, significantly alter the band gap and can be used in band gap engineering of nanoribbons.
    Keywords: ATK; Application; graphene; doping;
    Area: graphene
    BibTeX: 
    @article{Jaiswal2011,
  author = {Neeraj K. Jaiswal and Pankaj Srivastava},
  title = {First principles calculations of armchair graphene nanoribbons interacting with Cu atoms},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2011},
  volume = {44},
  number = {1},
  pages = {75-79},
  doi = {http://dx.doi.org/10.1016/j.physe.2011.07.009}
}
    Sudhanshu Choudhary & S. Qureshi Theoretical study on transport properties of a BN co-doped SiC nanotube

    [Abstract] [BibTeX]

    		 2011 Physics Letters A
    Vol. 375(38), 3382-3385     		 DOI  
    Abstract: We investigate the electronic transport properties of silicon carbide nanotubes (SiCNT) in presence of both boron (B) and nitrogen (N) impurities. The results show that co-doping BN impurities suppresses the important negative differential resistance (NDR) property. NDR suppression is attributed to the introduction of new electronic states near the Fermi level followed by weak orbital localization. BN co-doping results in exponential current-voltage (I-V ) characteristics which is in contrast to linear I-V characteristics for individual boron and nitrogen doped SiCNTs. HOMO has no contribution from B impurity, whereas, LUMO has contribution from N impurity at low and high bias.
    Keywords: Ab initio; SiC nanotube; impurities; co-doping; doping; negative differential resistance; NDR; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Choudhary2011a,
  author = {Sudhanshu Choudhary and S. Qureshi},
  title = {Theoretical study on transport properties of a BN co-doped SiC nanotube},
  journal = {Physics Letters A},
  year = {2011},
  volume = {375},
  number = {38},
  pages = {3382-3385},
  doi = {http://dx.doi.org/10.1016/j.physleta.2011.08.001}
}
    D.D. Wu, F. Jiang, G. Yin, H. Chen, Y.Y. Liang, H. Mizuseki & Y. Kawazoe Hydrogenation-chain-opened conductive channels in zigzag graphene nanoribbons

    [Abstract] [BibTeX]

    		 2011 Journal of Applied Physics
    Vol. 110(3), 033712     		 DOI  
    Abstract: We discover a method of opening the conductive channels of zigzag graphene nanoribbons (ZGNRs) by using hydrogenation chains to separate the nanoribbon into two strips with a -0.7 Å distance, although the overall hydrogenation on graphene transforms the highly conductive semimetal sheet into an insulator. Two edge-like states emerge around each hydrogenation chain. The conductance enhancement, made by the hydrogenation chain, is found in nanoribbons with 5 to 7 chains, e.g. 5ZGNRH, 6ZGNRH, 7ZGNRH, and 7ZGNR2H (7ZGNR with two hydrogenation chains). The ZGNRs with hydrogenation chains illustrate their potential in nanoelectronics and carbon electronics as electronic leads and nonlinear devices.
    Keywords: graphene; hydrogenation; nanostructured materials; narrow band gap semiconductors; spin polarised transport; topological insulators; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Wu2011a,
  author = {D. D. Wu and F. Jiang and G. Yin and H. Chen and Y. Y. Liang and H. Mizuseki and Y. Kawazoe},
  title = {Hydrogenation-chain-opened conductive channels in zigzag graphene nanoribbons},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2011},
  volume = {110},
  number = {3},
  pages = {033712},
  doi = {http://dx.doi.org/10.1063/1.3614496}
}
    Z.Z. Lin & X.J. Ning Controlling the electronic properties of monatomic carbon chains

    [Abstract] [BibTeX]

    		 2011 Europhysics Letters
    Vol. 95(4), 47012     		 DOI  
    Abstract: Based on ab initio calculations, it is shown that the energy gap of pure monatomic carbon chains can be changed from 0.27 up to 1.42 eV when the chain is stretched by 10%, and the chains can be turned into n-type or p-type semiconductors by doping (B, N, Si, P) atoms or into rectification device by doping the BN molecule. The doping process was proved by Car-Parrinello molecular dynamics, and the lifetime of the doped chains is predicted to be about 10^70 years at room temperature. The results suggest that short monatomic carbon chains are a good candidate for tunable laser medium.
    Keywords: ATK; Application; atomic chain; quantum wire; doping; linear carbon; nanotube; electroluminescence; graphene; transport; junction; devices;
    Area: molecular electronics; nanowires
    BibTeX: 
    @article{Lin2011,
  author = {Z. Z. Lin and X. J. Ning},
  title = {Controlling the electronic properties of monatomic carbon chains},
  journal = {Europhysics Letters},
  year = {2011},
  volume = {95},
  number = {4},
  pages = {47012},
  doi = {http://dx.doi.org/10.1209/0295-5075/95/47012}
}
    Ali Hossain Khan, Qingmin Ji, Katsuhiko Ariga, Bidisa Das, D.D. Sarma & Somobrata Acharya Synthesis and metallic probe induced conductance of Au tipped ultranarrow PbS rods

    [Abstract] [BibTeX]

    		 2011 Chem. Commun.
    Vol. 47(29), 8421-8423     		 DOI  
    Abstract: Au tipped ultranarrow PbS nanorods are synthesized. DFT electronic structure calculations and transport studies show that Au probes modify the nature and energies of PbS nanorod orbitals creating efficient electron conduction channels for enhanced conductance even at low applied bias.
    Keywords: ATK; Application; nanorod; nanowire; conductance;
    Area: nanowires
    BibTeX: 
    @article{Khan2011,
  author = {Khan, Ali Hossain and Ji, Qingmin and Ariga, Katsuhiko and Das, Bidisa and Sarma, D. D. and Acharya, Somobrata},
  title = {Synthesis and metallic probe induced conductance of Au tipped ultranarrow PbS rods},
  journal = {Chem. Commun.},
  publisher = {The Royal Society of Chemistry},
  year = {2011},
  volume = {47},
  number = {29},
  pages = {8421--8423},
  doi = {http://dx.doi.org/10.1039/C1CC12339D}
}
    Yuqing Xu, Changfeng Fang, Bin Cui, Guomin Ji, Yaxin Zhai & Desheng Liu Gated electronic currents modulation and designs of logic gates with single molecular field effect transistors

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 99(4), 043304     		 DOI  
    Abstract: The electronic transport properties of a gated single 1,3-benzenedithiol molecular device are studied by using nonequilibrium Green's function in combination with density functional theory, which is hoped to complement the experiments. The results show that the external transverse gate electrodes can effectively tune the electronic transport properties of the molecular devices. Negative differential resistance behaviors are observed almost at the same source-drain bias when applied different gate voltages. Mechanisms are proposed for these phenomena. Designs of using one gated molecular device to realize five basic logic gates are also put forward.
    Keywords: density functional theory; Green's function methods; logic gates; molecular electronics; organic compounds; organic field effect transistors; quantum transport; switch; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Xu2011,
  author = {Yuqing Xu and Changfeng Fang and Bin Cui and Guomin Ji and Yaxin Zhai and Desheng Liu},
  title = {Gated electronic currents modulation and designs of logic gates with single molecular field effect transistors},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {99},
  number = {4},
  pages = {043304},
  doi = {http://dx.doi.org/10.1063/1.3615691}
}
    Yi-Peng An, Zhongqin Yang & Mark A. Ratner High-efficiency switching effect in porphyrin-ethyne-benzene conjugates

    [Abstract] [BibTeX]

    		 2011 Journal of Chemical Physics
    Vol. 135(4), 044706     		 DOI  
    Abstract: We have explored the electronic transport properties of porphyrin-ethyne-benzene conjugates using an ab initio method. The results indicate that these ethyne-bridged phenyl porphyrin molecules can be used as candidates for molecular switching devices. The coplanar conformation of phenyl and porphyrin moieties allows a far larger current than the perpendicular conformation due to the near vanishing overlap of the frontier molecular orbitals (pi channels) in the porphyrin and phenyl parts in the latter. Higher current ratios of ON/OFF states can be obtained if amino or nitro substituent is placed at the position meta to the bridge connecting the pi systems of the molecule. The substituent group affects the electronic state energy of the entire molecule in coplanar conformation, while only affecting the local part in perpendicular conformation. More complex ethyne-bridged diphenyl porphyrin molecules are found to yield more complex and interesting switching effects. Our results suggest that such molecular wires composed of appropriate pi-conjugated molecules, can generally display perfect switching function and the efficiency can be tuned flexibly by adding certain substituent groups to the conjugates.
    Keywords: ab initio calculations; electrical conductivity transitions; molecular electronics; organic compounds; single-molecule junction; electron-transfer; controlled conductance; transport; transistor; dependence; resistance; geometry; wires; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{An2011,
  author = {Yi-Peng An and Zhongqin Yang and Mark A. Ratner},
  title = {High-efficiency switching effect in porphyrin-ethyne-benzene conjugates},
  journal = {Journal of Chemical Physics},
  publisher = {AIP},
  year = {2011},
  volume = {135},
  number = {4},
  pages = {044706},
  doi = {http://dx.doi.org/10.1063/1.3615492}
}
    L.H. Wang, Y. Guo & B.J. Ding Effect of the encapsulation of Li atom on the electronic transport properties of C20F20 cage

    [Abstract] [BibTeX]

    		 2011 Physica B: Condensed Matter
    Vol. 406(18), 3442 - 3445     		 DOI URL 
    Abstract: Carrying out theoretical calculations using a self-consistent ab initio approach that combines the non-equilibrium Green's function formalism with density functional theory, we investigate the effect of the center encapsulation of Li atom on the electronic transport properties of C20F20 cage sandwiched between two bulk gold electrodes. The results show that the electrical conductivity of the endohedral complex Li@C20F20 becomes better than that of the empty C20F20 in the bias voltages ranging from 0 to 1.2 V. The novel negative differential resistance behavior in the I-V characteristic curves can be observed by inserting Li atom into C20F20 cage. The mechanism for the negative differential resistance behavior of Li@C20F20 is suggested.
    Keywords: density functional theory; non-equilibrium green's function; electronic transport property; negative differential resistance; single-molecule conductance; complexes; junctions; rectification; transistor; surfaces; exchange; contact; thiol; cage molecule; ATK; Application
    Area: molecular electronics; fullerenes
    BibTeX: 
    @article{Wang2011b,
  author = {L.H. Wang and Y. Guo and B.J. Ding},
  title = {Effect of the encapsulation of Li atom on the electronic transport properties of C20F20 cage},
  journal = {Physica B: Condensed Matter},
  year = {2011},
  volume = {406},
  number = {18},
  pages = {3442 - 3445},
  url = {http://www.sciencedirect.com/science/article/pii/S0921452611005655},
  doi = {http://dx.doi.org/10.1016/j.physb.2011.06.016}
}
    P. Zhao, D.S. Liu, Y. Zhang, Y. Su, S.J. Li & G. Chen Negative differential resistance in the unsymmetrical C121-based molecular junction

    [Abstract] [BibTeX]

    		 2011 Physics Letters A
    Vol. 375(27), 2639-2643     		 DOI URL 
    Abstract: Using first-principles density functional theory and non-equilibrium Green's function formalism for quantum transport calculation, we have investigated the electronic transport properties of the unsymmetrical C121-based molecular junction. Our results show that the current-voltage curve displays a negative differential resistance phenomenon in a certain bias voltage range. The mechanism for the negative differential resistance phenomenon is suggested. The present findings could be helpful for the application of the C121 molecule in the field of single molecular devices or nanometer electronics.
    Keywords: Fullerenes; Non-equilibrium Green's function; Electronic transport; Negative differential resistance; ATK; Application
    Area: fullerenes
    BibTeX: 
    @article{Zhao2011c,
  author = {Zhao, P. and Liu, D.S. and Zhang, Y. and Su, Y. and Li, S.J. and Chen, G.},
  title = {Negative differential resistance in the unsymmetrical C121-based molecular junction},
  journal = {Physics Letters A},
  year = {2011},
  volume = {375},
  number = {27},
  pages = {2639--2643},
  url = {http://www.sciencedirect.com/science/article/pii/S0375960111006426},
  doi = {http://dx.doi.org/10.1016/j.physleta.2011.05.044}
}
    Vihar P. Georgiev & John E. McGrady Influence of Low-Symmetry Distortions on Electron Transport through Metal Atom Chains: When Is a Molecular Wire Really "Broken"?

    [Abstract] [BibTeX]

    		 2011 Journal of the American Chemical Society
    Vol. 133(32), 12590-12599     		 DOI  
    Abstract: In the field of molecular electronics, an intimate link between the delocalization of molecular orbitals and their ability to support current flow is often assumed. Delocalization, in turn, is generally regarded as being synonymous with structural symmetry, for example, in the lengths of the bonds along a molecular wire. In this work, we use density functional theory in combination with nonequilibrium Green's functions to show that precisely the opposite is true in the extended metal atom chain Cr3(dpa)4(NCS)2 where the delocalized pi framework has previously been proposed to be the dominant conduction pathway. Low-symmetry distortions of the Cr3 core do indeed reduce the effectiveness of these pi channels, but this is largely irrelevant to electron transport at low bias simply because they lie far below the Fermi level. Instead, the dominant pathway is through higher-lying orbitals of sigma symmetry, which remain essentially unperturbed by even quite substantial distortions. In fact, the conductance is actually increased marginally because the sigma-nb channel is displaced upward toward the Fermi level. These calculations indicate a subtle and counterintuitive relationship between structure and function in these metal chains that has important implications for the interpretation of data emerging from scanning tunnelling and atomic force microscopy experiments.
    Keywords: ATK; Application; molecular electronics; delocalization; molecular orbitals; metal atom chain; conductance
    Area: molecular electronics
    BibTeX: 
    @article{Georgiev2011,
  author = {Georgiev, Vihar P. and McGrady, John E.},
  title = {Influence of Low-Symmetry Distortions on Electron Transport through Metal Atom Chains: When Is a Molecular Wire Really "Broken"?},
  journal = {Journal of the American Chemical Society},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {133},
  number = {32},
  pages = {12590-12599},
  doi = {http://dx.doi.org/10.1021/ja2028475}
}
    Hua Hao, XiaoHong Zheng, ZhenXiang Dai & Zhi Zeng Gate-induced switching in single-molecule magnet Mn(III)Cu(II)

    [Abstract] [BibTeX]

    		 2011 Journal of Applied Physics
    Vol. 110(2), 023702     		 DOI  
    Abstract: Gate voltage effect on electronic transport through the smallest single-molecule magnet (SMM) MnCu [MnIIICuIICl(5-Br-sap)2(MeOH)] sandwiched between Au(100) electrodes is investigated by spin-polarized density functional theory calculations combined with the Keldysh nonequilibrium Green's technique. Our study demonstrates that a certain gate voltage can induce a switching of the conductance in the equilibrium state. Under a finite bias voltage, negative differential resistance is observed in this system and can be modulated by tuning the gate voltage. More interestingly, current rectification can be achieved at a certain negative gate voltage. These effects can be understood by the responses of the benzene rings and the magnetic core to an external electrical field.
    Keywords: transport; magnetization; spin; molecular electronics; density functional theory; electrical resistivity; gold; Green's function methods; magnetic materials; molecular magnetism; organic compounds; rectification; spin polarised transport; switching; ATK; Application
    Area: molecular electronics; spin
    BibTeX: 
    @article{Hao2011,
  author = {Hua Hao and XiaoHong Zheng and ZhenXiang Dai and Zhi Zeng},
  title = {Gate-induced switching in single-molecule magnet Mn(III)Cu(II)},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2011},
  volume = {110},
  number = {2},
  pages = {023702},
  doi = {http://dx.doi.org/10.1063/1.3610448}
}
    Kai-Tak Lam, Marie Stephen Leo, Chengkuo Lee & Gengchiau Liang Design evaluation of graphene nanoribbon nanoelectromechanical devices

    [Abstract] [BibTeX]

    		 2011 Journal of Applied Physics
    Vol. 110(2), 024302     		 DOI  
    Abstract: Computational studies on nanoelectromechanical switches based on bilayer graphene nanoribbons (BGNRs) with different designs are presented in this work. By varying the interlayer distance via electrostatic means, the conductance of the BGNR can be changed in order to achieve ON-states and OFF-states, thereby mimicking the function of a switch. Two actuator designs based on the modified capacitive parallel plate (CPP) model and the electrostatic repulsive force (ERF) model are discussed for different applications. Although the CPP design provides a simple electrostatic approach to changing the interlayer distance of the BGNR, their switching gate bias VTH strongly depends on the gate area, which poses a limitation on the size of the device. In addition, there exists a risk of device failure due to static fraction between the mobile and fixed electrodes. In contrast, the ERF design can circumvent both issues with a more complex structure. Finally, optimizations of the devices are carried out in order to provide insights into the design considerations of these nanoelectromechanical switches.
    Keywords: actuators; fullerene devices; graphene; nanoelectromechanical devices; nanostructured materials; switches; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Lam2011a,
  author = {Kai-Tak Lam and Marie Stephen Leo and Chengkuo Lee and Gengchiau Liang},
  title = {Design evaluation of graphene nanoribbon nanoelectromechanical devices},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2011},
  volume = {110},
  number = {2},
  pages = {024302},
  doi = {http://dx.doi.org/10.1063/1.3606578}
}
    Jing Zeng, Ke-Qiu Chen, Jun He, Zhi-Qiang Fan & Xiao-Jiao Zhang Nitrogen doping-induced rectifying behavior with large rectifying ratio in graphene nanoribbons device

    [Abstract] [BibTeX]

    		 2011 Journal of Applied Physics
    Vol. 109(12), 124502     		 DOI  
    Abstract: By applying nonequilibrium Green's functions in combination with density-function theory, we investigate the electronic transport properties of armchair graphene nanoribbons devices with one undoped and one nitrogen-doped armchair graphene nanoribbons electrode. For the doped armchair graphene nanoribbons electrode, an N dopant is considered to substitute the center or edge carbon atom. The results show that the electronic transport properties are strongly dependent on the width of the ribbon and the position of the N dopant. The rectifying behavior with large rectifying ratio can be observed and can be modulated by changing the width of the ribbon or the position of the N dopant. A mechanism for the rectifying behavior is suggested.
    Keywords: density functional theory; graphene; Green's function methods; nanostructured materials; nitrogen; rectification; semiconductor doping; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Zeng2011d,
  author = {Jing Zeng and Ke-Qiu Chen and Jun He and Zhi-Qiang Fan and Xiao-Jiao Zhang},
  title = {Nitrogen doping-induced rectifying behavior with large rectifying ratio in graphene nanoribbons device},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2011},
  volume = {109},
  number = {12},
  pages = {124502},
  doi = {http://dx.doi.org/10.1063/1.3600067}
}
    A. Zienert, J. Schuster, R. Streiter & T. Gessner Quantum mechanical methods for the simulation of electronic transport through carbon nanotubes

    [Abstract] [BibTeX]

    		 2011 Interconnect Technology Conference and 2011 Materials for Advanced Metallization (IITC/MAM), 2011 IEEE International, 1 -3  DOI  
    Abstract: In the present work we study electronic transport properties of finite length single-wall carbon nanotubes. A simple model is used to describe the electrodes and the way they are attached to both ends of the CNT. Electronic transport calculations are carried out on three different levels of sophistication. Those are single orbital tight-binding, extended Hückel and density functional theory in combination with Green's function methods. Results are compared and discussed.
    Keywords: ATK; ATK-SE; Application; nanotube;
    Area: nanotubes
    BibTeX: 
    @inproceedings{Zienert2011,
  author = {Zienert, A. and Schuster, J. and Streiter, R. and Gessner, T.},
  title = {Quantum mechanical methods for the simulation of electronic transport through carbon nanotubes},
  booktitle = {Interconnect Technology Conference and 2011 Materials for Advanced Metallization (IITC/MAM), 2011 IEEE International},
  year = {2011},
  pages = {1 -3},
  doi = {http://dx.doi.org/10.1109/IITC.2011.5940363}
}
    William D. Wheeler, B.A. Parkinson & Yuri Dahnovsky The adsorption energy and diffusion of a pentacene molecule on a gold surface

    [Abstract] [BibTeX]

    		 2011 Journal of Chemical Physics
    Vol. 135(2), 024702     		 DOI  
    Abstract: The nature of the chemical bonding of a pentacene molecule to a gold surface is studied. The calculations are carried out using two very different methodologies, the ab inito gaussian molecular orbital method and a numerical atomic orbital method, developed from the well tested SIESTA approach. Using the GAUSSIAN 09 package, we employ both local density B3LYP, and long-range correlated functionals CAM-B3LYP, omega-B97, and omega-B97X. For comparison, we also calculate the adsorption energy using the ATOMISTIX TOOLKIT with the revised PBE functional. Within computational and experimental errors we find that the best description of the binding energies can be obtained from GAUSSIAN calculations using long-range omega-B97 and omega-B97X exchange functionals. Thus the nature of chemical bonding of a pentacene to gold is a van der Waals type. To understand the large variation in the geometries computed by different methods, we calculate energy profiles in both X- and Y-directions. The energy barriers appear to be very small and comparable with the value of room temperature. Thus a pentacene molecule moves on a gold surface with almost no friction at room temperatures. An estimation of the work function is often obtained from a simple electrostatic approach. We test this estimation and find that this approach cannot be used because it significantly underestimates the work function. This investigation gives insights into the structure and bonding of pentacene to a gold surface and provides ideas for the improvement of methodologies for computing the properties of van der Waals adsorbates.
    Keywords: ab initio calculations; adsorption; binding energy; bonds (chemical); density functional theory; diffusion; geometry; GO calculations; gold; organic compounds; molecular electronics; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Wheeler2011,
  author = {William D. Wheeler and B. A. Parkinson and Yuri Dahnovsky},
  title = {The adsorption energy and diffusion of a pentacene molecule on a gold surface},
  journal = {Journal of Chemical Physics},
  publisher = {AIP},
  year = {2011},
  volume = {135},
  number = {2},
  pages = {024702},
  doi = {http://dx.doi.org/10.1063/1.3599088}
}
    D.H. Zhang, K.L. Yao & G.Y. Gao The peculiar transport properties in p-n junctions of doped graphene nanoribbons

    [Abstract] [BibTeX]

    		 2011 Journal of Applied Physics
    Vol. 110(1), 013718     		 DOI  
    Abstract: Two kinds of junctions based on doped graphene nanoribbons (GNRs) are designed and studied in this article. One is the N-doped armchair GNR (AGNR) joined directly by B-doped AGNRs, and another is similar, but there is an undoped AGNR between them. The transport properties are calculated using the full self-consistent ab initio nonequilibrium Green's function and density-functional theory methods under external bias. We find that the I-V curves for both junctions have a striking nonlinear feature and show large negative differential resistance properties, not only at the positive bias but also at the negative one. The results also indicate that the diode-like properties are kept and the rectification coefficient is very high within a wide bias region. Our calculations reveal that the formation of these peculiar transport behaviors is due to the great changes of the transmission spectra and the projected self-consistent Hamiltonian eigenvalues with the applied bias voltage. These findings suggest that the doped AGNRs may offer unique opportunities for the future development of nanoscale electronics.
    Keywords: ab initio calculations; boron; density functional theory; eigenvalues and eigenfunctions; elemental semiconductors; graphene; Green's function methods; nanostructured materials; negative resistance; nitrogen; p-n heterojunctions; rectification; SCF calculations; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Zhang2011c,
  author = {D. H. Zhang and K. L. Yao and G. Y. Gao},
  title = {The peculiar transport properties in p-n junctions of doped graphene nanoribbons},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2011},
  volume = {110},
  number = {1},
  pages = {013718},
  doi = {http://dx.doi.org/10.1063/1.3605489}
}
    K Shiiki Simulation of tunneling magneto-resistance in Fe/MgO/Fe junction

    [Abstract] [BibTeX]

    		 2011 Journal of Physics: Conference Series
    Vol. 303(1), 012101     		 DOI URL 
    Abstract: The conductivity asymmetry of junctions with insulating MgO barriers embedded between ferromagnetic Fe electrodes has been investigated by the first principles calculation program of Atomistix ToolKit 2008. The conductivity in up-spin electron is larger than that in down-spin electron for the ideal structure. It leads to the large TMR ratio. The defect of O or Fe atoms hardly varies the conductivity in both up and down-spin electrons. The defect of Mg atoms increases the conductivity in down-spin electron, although the up-spin conductivity does not change very much. So the defect of Mg decreases the TMR ratio. The defect of Mg near the interface especially shows this degradation. The derivative conductivity dI / dV vs. V characteristics are asymmetric for the polarity of the bias voltage V according to the location of the atom defect. The quality of the junction in devices can be evaluated by the asymmetry.
    Keywords: ATK; Application; spin; magneto-resistance; MTJ; defects; strain
    Area: interfaces; spin; semi; nvm
    BibTeX: 
    @article{Shiiki2011,
  author = {K Shiiki},
  title = {Simulation of tunneling magneto-resistance in Fe/MgO/Fe junction},
  journal = {Journal of Physics: Conference Series},
  year = {2011},
  volume = {303},
  number = {1},
  pages = {012101},
  url = {http://stacks.iop.org/1742-6596/303/i=1/a=012101},
  doi = {http://dx.doi.org/10.1088/1742-6596/303/1/012101}
}
    Manabu Kiguchi, Takuya Takahashi, Yuta Takahashi, Yoshihiro Yamauchi, Takashi Murase, Makoto Fujita, Tomofumi Tada & Satoshi Watanabe Electron Transport through Single Molecules Comprising Aromatic Stacks Enclosed in Self-Assembled Cages

    [BibTeX]

    		 2011 Angewandte Chemie International Edition
    Vol. 50(25), 5708-5711     		 DOI  
    Keywords: electron transfer; molecular electronics; nanogap electrode; pi interactions; single-molecule studies; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Kiguchi2011a,
  author = {Kiguchi, Manabu and Takahashi, Takuya and Takahashi, Yuta and Yamauchi, Yoshihiro and Murase, Takashi and Fujita, Makoto and Tada, Tomofumi and Watanabe, Satoshi},
  title = {Electron Transport through Single Molecules Comprising Aromatic Stacks Enclosed in Self-Assembled Cages},
  journal = {Angewandte Chemie International Edition},
  publisher = {WILEY-VCH Verlag},
  year = {2011},
  volume = {50},
  number = {25},
  pages = {5708--5711},
  doi = {http://dx.doi.org/10.1002/anie.201100431}
}
    Xiao-Fei Li, Ling-Ling Wang, Ke-Qiu Chen & Yi Luo Design of Graphene-Nanoribbon Heterojunctions from First Principles

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(25), 12616-12624     		 DOI  
    Abstract: Graphene nanoribbons with armchair and zigzag edges are known to have very different electronic structure and properties. We show here that the fusion of an armchair and a zigzag graphene-nanoribbon (aGNR|zGNR) can form heterojunctions with remarkable electron transport properties. First-principles calculations reveal that the heterojunction can be either metallic or semiconducting depending on the width of the nanoribbon. A well-defined oscillation of the zero-bias conductance as a function of the ribbon width is observed, which is originated from the resonance and nonresonance of frontier orbitals between aGNR and zGNR. We find that the current/voltage characteristics of the aGNR|zGNR heterojunction possess pronounced rectification effect, and a high rectification ratio can be achieved by tuning the width of the zGNR to minimize the backward current. The unique properties of the proposed heterojunction could be very useful for manufacturing graphene-based electronic devices.
    Keywords: ATK; Application; graphene nanoribbon heterojunction; rectification
    Area: graphene
    BibTeX: 
    @article{Li2011d,
  author = {Li, Xiao-Fei and Wang, Ling-Ling and Chen, Ke-Qiu and Luo, Yi},
  title = {Design of Graphene-Nanoribbon Heterojunctions from First Principles},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {25},
  pages = {12616-12624},
  doi = {http://dx.doi.org/10.1021/jp202188t}
}
    Qihang Liu, Guangfu Luo, Rui Qin, Hong Li, Xin Yan, Chengyong Xu, Lin Lai, Jing Zhou, Shimin Hou, Enge Wang, Zhengxiang Gao & Jing Lu Negative differential resistance in parallel single-walled carbon nanotube contacts

    [Abstract] [BibTeX]

    		 2011 Physical Review B
    Vol. 83(15), 155442-     		 DOI  
    Abstract: Based on first-principles calculations, we investigate the electron transport properties of parallel single-walled carbon nanotube contact. A significant negative differential resistance (NDR) behavior is found due to staggered electron gratings in energy space and standing waves in real space on the two tubes induced by bias. Such a NDR effect is robust against the contact length, the tube diameter, the shape of the end, and the difference in the two electrodes. Because no bridging molecule is used, the structure of this NDR device is simpler compared with ordinary molecular NDR devices. Our findings are expected to promote the discovery of more NDR devices composed of only two electrodes in parallel contact.
    Keywords: ATK; Application; nanotube; negative differential resistance; NDR
    Area: nanotubes
    BibTeX: 
    @article{Liu2011d,
  author = {Liu, Qihang and Luo, Guangfu and Qin, Rui and Li, Hong and Yan, Xin and Xu, Chengyong and Lai, Lin and Zhou, Jing and Hou, Shimin and Wang, Enge and Gao, Zhengxiang and Lu, Jing},
  title = {Negative differential resistance in parallel single-walled carbon nanotube contacts},
  journal = {Physical Review B},
  publisher = {American Physical Society},
  year = {2011},
  volume = {83},
  number = {15},
  pages = {155442--},
  doi = {http://dx.doi.org/10.1103/PhysRevB.83.155442}
}
    Pei Zhao, Ji-Ming Zheng, You-Wei Chen, Ping Guo & Zhao-Yu Ren Theoretical investigation on electron transport properties of single wall carbon nanotube with oxygen molecular absorption

    [Abstract] [BibTeX]

    		 2011 Acta Physica Sinica
    Vol. 60(6), 068501     		 URL 
    Abstract: Electron transport properties of (4,4) single wall carbon nanotube as well as the nanotube with oxygen molecule absorption, are investigated by using first principles analysis. The results show that electron current through the nanotube with oxygen molecule absorption system increases linearly under low bias ranging from 0 to 1.1 V, while the bias is larger than 1.1 V, the current through this system increases slowly. It is also shown that absorbed oxygen molecule brings two kinds of influence on the properties of electron transport: first, the oxygen molecular absorbed states afford new channels to electron transport and enhance the transmission. Second, the oxygen molecular absorbed states spoil the nanotube's symmetry and enhance the electron scattering, so reduce the transmission.
    Keywords: ATK; Application; single wall carbon nanotube; oxygen molecular absorption; electron transport; non-equilibrium Green's functions
    Area: nanotubes
    BibTeX: 
    @article{Zhao2011a,
  author = {Zhao, Pei and Zheng, Ji-Ming and Chen, You-Wei and Guo, Ping and Ren, Zhao-Yu},
  title = {Theoretical investigation on electron transport properties of single wall carbon nanotube with oxygen molecular absorption},
  journal = {Acta Physica Sinica},
  year = {2011},
  volume = {60},
  number = {6},
  pages = {068501},
  url = {http://wulixb.iphy.ac.cn/cn/ch/common/view_abstract.aspx?file_no=w201106119&flag=1}
}
    S. Choudhary & S. Qureshi Effect of radial and axial deformation on electron transport properties in a semiconducting Si-C nanotube

    [Abstract] [BibTeX]

    		 2011 Journal of Nano- and Electronic Physics
    Vol. 3(1), 584-589     		 URL 
    Abstract: We study the bias voltage dependent current characteristic in a deformed (8, 0) silicon carbide nanotube by applying self consistent non-equilibrium Green's function formalism in combination with the density-functional theory to a two probe molecular junction constructed from deformed nanotube. The transmission spectra and electron density of states at zero bias shows a significant reduction in threshold in the case of both radially compressed and axially elongated nanotube. However, semiconductor to metal transition was not observed, though the results show large differences in current characteristic compared to a perfect nanotube.
    Keywords: ATK; Application; nanotubes; SiC; defects; deformation;
    Area: nanotubes
    BibTeX: 
    @article{Choudhary2011,
  author = {S. Choudhary and S. Qureshi},
  title = {Effect of radial and axial deformation on electron transport properties in a semiconducting Si-C nanotube},
  journal = {Journal of Nano- and Electronic Physics},
  year = {2011},
  volume = {3},
  number = {1},
  pages = {584-589},
  url = {http://jnep.sumdu.edu.ua/index.php?option=com_content&task=full_article&id=212&lang=en}
}
    YaXin Zhai, GuoMin Ji, ChangFeng Fang, Bin Cui, Peng Zhao & DeSheng Liu Negative differential resistance in molecular devices: the role of molecule-electrode coupling

    [Abstract] [BibTeX]

    		 2011 SCIENCE CHINA Physics, Mechanics & Astronomy
    Vol. 54(8), 1455-1460     		 DOI  
    Abstract: By applying nonequilibrium Green's function formalism combined with the first-principles density functional theory, we investigate the electronic transport in two molecular junctions constituted by a substituted oligo (phenylene ehtynylene) sandwiched between two Au electrodes. Our calculations show that the weak molecule-electrode coupling is responsible for the observation of the negative differential resistance (NDR) effect in experiments. When the coupling is weak, the projected density of states (PDOS) of the molecule and the electrodes undergoes a mismatch-match-mismatch procedure, which increases and then decreases the transmission peak intensities, leading to a NDR effect. We also find that the localization/delocalization of the molecular orbitals and the change of charge state of the molecule have no direct relation with the NDR effect, because they change little as the voltage increases.
    Keywords: ATK; Application; molecular electronics; negative differential resistance; NDR; substituted oligo (phenylene ehtynylene); molecular junction; density functional theory; nonequilibrium Green's function formalism
    Area: molecular electronics
    BibTeX: 
    @article{Zhai2011,
  author = {Zhai, YaXin and Ji, GuoMin and Fang, ChangFeng and Cui, Bin and Zhao, Peng and Liu, DeSheng},
  title = {Negative differential resistance in molecular devices: the role of molecule-electrode coupling},
  journal = {SCIENCE CHINA Physics, Mechanics & Astronomy},
  publisher = {Science China Press, co-published with Springer},
  year = {2011},
  volume = {54},
  number = {8},
  pages = {1455-1460},
  doi = {http://dx.doi.org/10.1007/s11433-011-4406-x}
}
    Zhi-Qiang Fan & Ke-Qiu Chen Controllable rectifying performance in a C60 molecular device with asymmetric electrodes

    [Abstract] [BibTeX]

    		 2011 Journal of Applied Physics
    Vol. 109(12), 124505     		 DOI URL 
    Abstract: By using nonequilibrium Green's functions in combination with the density-functional theory, we investigate the current-voltage character of a single C60 molecule sandwiched between Au electrode and carbon nanotube electrode theoretically. The calculated results show that the asymmetric electrodes connecting is of significant influence on the transport properties. By adjusting the matching of orbitals around the Fermi level among the two electrodes and the molecule, the rectifying behavior of the device can be realized and the rectification ratio can be modulated.
    Keywords: carbon nanotubes; density functional theory; electrodes; Fermi level; fullerene devices; fullerenes; gold; Green's function methods; metal-insulator boundaries; rectification; ATK; Application
    Area: nanotubes; fullerenes
    BibTeX: 
    @article{Fan2011,
  author = {Zhi-Qiang Fan and Ke-Qiu Chen},
  title = {Controllable rectifying performance in a C60 molecular device with asymmetric electrodes},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2011},
  volume = {109},
  number = {12},
  pages = {124505},
  url = {http://link.aip.org/link/?JAP/109/124505/1},
  doi = {http://dx.doi.org/10.1063/1.3597789}
}
    Xinqian Li, Aleksandar Staykov & Kazunari Yoshizawa Orbital views of the electron transport through heterocyclic aromatic hydrocarbons

    [Abstract] [BibTeX]

    		 2011 Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)
    Vol. 130, 765-774     		 DOI  
    Abstract: Electron-transport properties of heterocyclic aromatic hydrocarbons are investigated with theoretical methods. The present study is based on a previously derived concept for orbital control of electron transport through aromatic hydrocarbons. The orbital control concept provided crucial basic understanding for the best conductance channels in the aromatic hydrocarbons and was successfully applied in the design of molecular devices. That concept was proven to hold true for small aromatic molecules, large polycyclic aromatic hydrocarbons with different edge structures, and in weak and strong coupling with the electrodes junctions. The polycyclic aromatic hydrocarbons and nanographenes used in the molecular electronics are often immobilized with different types of defects, which require the application of the orbital control concept on heterocyclic aromatic hydrocarbons. In this work, the effect of the heteroatoms in aromatic hydrocarbons on their electron-transport properties and the applicability of the orbital control concept on heterocyclic aromatic hydrocarbons are studied. Effective routes for electron transport are predicted in weak coupling junctions by analyzing the phase and amplitude of the frontier orbitals. The qualitative predictions are made with the nonequilibrium Green's function method combined with the Hückel approximation. Quantitative, first principle calculations are performed with the nonequilibrium Green's function method combined with density functional theory. The obtained results are in good agreement with the expectations on the basis of the orbital control concept, which proves its applicability in heterocyclic aromatic hydrocarbons.
    Keywords: ATK; Application; molecular electronics; nonequilibrium Green's function; orbital symmetry rule; electron-transport properties; heterocyclic aromatic hydrocarbons
    Area: molecular electronics
    BibTeX: 
    @article{Li2011c,
  author = {Li, Xinqian and Staykov, Aleksandar and Yoshizawa, Kazunari},
  title = {Orbital views of the electron transport through heterocyclic aromatic hydrocarbons},
  journal = {Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)},
  publisher = {Springer Berlin / Heidelberg},
  year = {2011},
  volume = {130},
  pages = {765-774},
  doi = {http://dx.doi.org/10.1007/s00214-011-0968-y}
}
    JiaSai Ma, DongMei Li, YaXin Zhai & Peng Zhao Negative differential resistance in a molecular junction of carbon nanotube and benzene

    [Abstract] [BibTeX]

    		 2011 SCIENCE CHINA Physics, Mechanics & Astronomy
    Vol. 54(8), 1433-1437     		 DOI  
    Abstract: We propose a novel molecular junction with single-walled carbon nanotubes as electrodes bridged by a benzene molecule, in which the electrodes are saturated by different terminations (C-, H- and N-). It is found that the different terminations at the carbon nanotube ends strongly affect the electronic transport properties of the junction. The current-voltage (I-V) curve of the N-terminated carbon nanotube junction shows a more striking nonlinear feature than that of the C- and H-terminated junctions at small bias. Moreover, the negative differential resistance behaviors can be observed significantly in the N-terminated carbon nanotube junction, whereas not in the other two cases.
    Keywords: ATK; Application; negative differential resistance; carbon nanotube; electronic transport; non-equilibrium Green's function
    Area: nanotubes
    BibTeX: 
    @article{Ma2011,
  author = {Ma, JiaSai and Li, DongMei and Zhai, YaXin and Zhao, Peng},
  title = {Negative differential resistance in a molecular junction of carbon nanotube and benzene},
  journal = {SCIENCE CHINA Physics, Mechanics & Astronomy},
  publisher = {Science China Press, co-published with Springer},
  year = {2011},
  volume = {54},
  number = {8},
  pages = {1433-1437},
  doi = {http://dx.doi.org/10.1007/s11433-011-4392-z}
}
    Zhizhou Yu, M.L. Hu, C.X. Zhang, C.Y. He, L.Z. Sun & Jianxin Zhong Transport Properties of Hybrid Zigzag Graphene and Boron Nitride Nanoribbons

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(21), 10836-10841     		 DOI URL 
    Abstract: The transport properties of hybrid nanoribbons formed by partially substituting zigzag boron nitride (graphene) nanoribbons into zigzag graphene (boron nitride) nanoribbons are investigated using the first-principles nonequilibrium Green's function method. The transport properties are highly improved with the transmission conductance around the Fermi level increasing to 3G0 in hybrid systems based on zigzag graphene nanoribbons and to 2G0 in hybrid systems based on zigzag boron nitride nanoribbons. The enhancement is attributed to the coupling effect between B (N) atoms and C atoms at the interface of hybrid systems, which introduces a pair of bonding and antibonding bands around the Fermi level. The transport enhancement also remains in hybrid nanoribbons sandwiched into gold electrodes. The currents of such devices are improved compared with those of pristine ones, which originate from the additional transport channels at the C-B interface.
    Keywords: ATK; Application; graphene; boron-nitride nanoribbon; transport properties; NEGF;
    Area: graphene
    BibTeX: 
    @article{Yu2011a,
  author = {Yu, Zhizhou and Hu, M. L. and Zhang, C. X. and He, C. Y. and Sun, L. Z. and Zhong, Jianxin},
  title = {Transport Properties of Hybrid Zigzag Graphene and Boron Nitride Nanoribbons},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {21},
  pages = {10836-10841},
  url = {http://pubs.acs.org/doi/abs/10.1021/jp200870t},
  doi = {http://dx.doi.org/10.1021/jp200870t}
}
    Salvador Rodríguez-Bolívar, Francisco M. Gómez-Campos, Luis Álvarez de Cienfuegos, Noelia Fuentes, Diego J. Cárdenas, Elena Buñuel, Juan E. Carceller, Andrés Parra & Juan M. Cuerva Conductance and application of organic molecule pairs as nanofuses

    [Abstract] [BibTeX]

    		 2011 Physical Review B
    Vol. 83(12), 125424     		 DOI  
    Abstract: We propose that a pair of organic molecules can mimic the behavior of a macroscopic fuse at nanoscale, one component of the pair being the on state and the other the off state. For this task we make use of density-functional theory to calculate the physical properties of selected molecules, which have also been synthesized by our team. By this means we obtain the transmission spectra and the current of the proposed devices, which allows us to compare the behavior of the on and off states. Of particular interest is the on/off switch ratios, defined as the current ratios of the on and off structures at the corresponding bias voltage. In a first stage, we examine the best linker between the device and the electrode for high on/off switch ratios. Once this is determined, we test the influence of the electron richness of the system to provide a high on/off switch ratio. The entire analysis is also supported by the molecular projected self-consistent Hamiltonian, which provides a good way of understanding the molecular behavior. All the calculations support that interesting on/off switch ratios of two orders of magnitude could be obtained with these prototypical nanofuses.
    Keywords: ATK; Application; molecular electronics; nanoscale fuse; nanofuse; experimental comparison;
    Area: molecular electronics
    BibTeX: 
    @article{PhysRevB.83.125424,
  author = {Rodríguez-Bolívar, Salvador and Gómez-Campos, Francisco M. and Álvarez de Cienfuegos, Luis and Fuentes, Noelia and Cárdenas, Diego J. and Buñuel, Elena and Carceller, Juan E. and Parra, Andrés and Cuerva, Juan M.},
  title = {Conductance and application of organic molecule pairs as nanofuses},
  journal = {Physical Review B},
  publisher = {American Physical Society},
  year = {2011},
  volume = {83},
  number = {12},
  pages = {125424},
  doi = {http://dx.doi.org/10.1103/PhysRevB.83.125424}
}
    Satyendra Singh Chauhan, Pankaj Srivastava & Rajnish Kurchania Half-Metallicity in Doped Armchair Graphene Nanoribbons - An Ab Initio Approach

    [Abstract] [BibTeX]

    		 2011 Journal of Computational and Theoretical Nanoscience
    Vol. 8, 729-735     		 DOI URL 
    Abstract: We present a comprehensive theoretical study based on density functional theory for stability, electronic and transport properties of armchair graphene nanoribbons. We have tested boron, beryllium, lithium, magnesium, fluorine, oxygen and nitrogen as substitutional dopant in the center of armchair graphene nanoribbons. It is observed that oxygen atom as substitutional dopant in armchair graphene nanoribbons is energetically more favorable and it also minimizes the band gap in all tested widths of armchair graphene nanoribbons (AGNRs). Moreover the oxygen doping at the center of ribbon predicts the half-metallicty in AGNRs. The transport properties are found to be influenced by edge doping of oxygen in AGNRs. These substitutional oxygen atoms act as scattering centers for the electronic transport along the nanoribbons. Since transmission is sensitive to O doping, so our results point towards the relative suitability of O doped armchair edge for sensor applications.
    Keywords: ATK; Application; half-metallicity; doping; graphene nanoribbons
    Area: graphene; spin
    BibTeX: 
    @article{Chauhan2011,
  author = {Chauhan, Satyendra Singh and Srivastava, Pankaj and Kurchania, Rajnish},
  title = {Half-Metallicity in Doped Armchair Graphene Nanoribbons - An Ab Initio Approach},
  journal = {Journal of Computational and Theoretical Nanoscience},
  year = {2011},
  volume = {8},
  pages = {729-735},
  url = {http://www.ingentaconnect.com/content/asp/jctn/2011/00000008/00000004/art00029},
  doi = {http://dx.doi.org/10.1166/jctn.2011.1745}
}
    Hongguang Cheng, Zuli Liu & Kailun Yao Rectifying behavior in La[sub 2/3]Sr[sub 1/3]MnO[sub 3]/MgO/SrRuO[sub 3] magnetic tunnel junctions

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 98(17), 172107     		 DOI URL 
    Abstract: We report first principles calculations of transport properties of the all-oxide La2/3Sr1/3MnO3/MgO/SrRuO3 magnetic tunnel junctions. A sizeable rectifying behavior which can be enhanced by increasing the MgO barrier thickness is predicted theoretically. For the device with 13 layers of MgO barrier, the positive current is about two orders of magnitude larger than the reverse leakage current. The rectifying behavior arises from the symmetry-filtering properties of the MgO barrier. This rectifying effect which is totally dominated by quantum tunneling could be used to design faster quantum devices such as tunnel diode and tunnel transistor.
    Keywords: ab initio calculations; interface magnetism; lanthanum compounds; leakage currents; magnesium compounds; magnetic tunnelling junction; rectification; strontium compounds; ATK; Application; MTJ; spin
    Area: interfaces; spin; semi; nvm
    BibTeX: 
    @article{Cheng2011a,
  author = {Hongguang Cheng and Zuli Liu and Kailun Yao},
  title = {Rectifying behavior in La[sub 2/3]Sr[sub 1/3]MnO[sub 3]/MgO/SrRuO[sub 3] magnetic tunnel junctions},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {98},
  number = {17},
  pages = {172107},
  url = {http://link.aip.org/link/?APL/98/172107/1},
  doi = {http://dx.doi.org/10.1063/1.3586242}
}
    Morad M. El-Hendawy, Ahmed M. El-Nahas & Mohamed K. Awad The effect of constitutional and conformational isomerization on the electrical properties of diblock molecular diode

    [Abstract] [BibTeX]

    		 2011 Organic Electronics
    Vol. 12(6), 1080 - 1092     		 DOI URL 
    Abstract: The ultimate goal of this paper is to introduce new links between the chemical response of the molecule to the electric field and the physics of cell involving the molecule. Density functional theory (DFT) calculations were preformed to investigate the effect of constitutional and conformational isomerization on the electrical properties of the dipyrimidinyl-diphenyl dithiol (DPDPh1) as a diblock molecular diode. The non-equilibrium Green's function approach combined with DFT (NEGF-DFT) has been used to compute the current-voltage characteristics in order to support the obtained results. The calculations could differentiate among the isomers regarding their rectification efficiency. Moreover, plots of the global electrophilicity index and the tendency of constitutional isomers to receive charge from the circuit against applied voltage show I-V curve feature. The conformational analysis has been done through examining the effect of structural twist on the current, dipole moment, HOMO energy, and molecular gain of the DPDPh1 molecule. The rectification is slightly affected by twisting because of the limited change in molecular polarization. However, the results demonstrated that the insertion of a CH2-spacer or twisting the donor and acceptor parts of the DPDPh1 molecule by 90° generates an Aviram-Ratner-like diode where the HOMO and LUMO are localized on the donor and acceptor subunits, respectively.
    Keywords: molecular diode; ATK; Application; electrophilicity; rectification
    Area: molecular electronics
    BibTeX: 
    @article{El-Hendawy2011,
  author = {Morad M. El-Hendawy and Ahmed M. El-Nahas and Mohamed K. Awad},
  title = {The effect of constitutional and conformational isomerization on the electrical properties of diblock molecular diode},
  journal = {Organic Electronics},
  year = {2011},
  volume = {12},
  number = {6},
  pages = {1080 - 1092},
  url = {http://www.sciencedirect.com/science/article/pii/S1566119911001017},
  doi = {http://dx.doi.org/10.1016/j.orgel.2011.03.022}
}
    Fang-Ping OuYang, Sheng-Lin Peng, Hua Zhang, Li-Bo Weng & Hui Xu A biosensor based on graphene nanoribbon with nanopores: a first-principles devices-design

    [Abstract] [BibTeX]

    		 2011 Chinese Physics B
    Vol. 20(5), 058504     		 DOI  
    Abstract: A biosensor device, built from graphene nanoribbons (GNRs) with nanopores, was designed and studied by first-principles quantum transport simulation. We have demonstrated the intrinsic transport properties of the device and the effect of different nucleobases on device properties when they are located in the nanopores of GNRs. It was found that the device's current changes remarkably with the species of nucleobases, which originates from their different chemical compositions and coupling strengths with GNRs. In addition, our first-principles results clearly reveal that the distinguished ability of a device's current depends on the position of the pore to some extent. These results may present a new way to read off the nucleobases sequence of a single-stranded DNA (ssDNA) molecule by such GNRs-based device with designed nanopores
    Keywords: ATK; Application; DNA; biosensors; graphene nanoribbon; defects;
    Area: graphene
    BibTeX: 
    @article{Fang-Ping2011,
  author = {OuYang, Fang-Ping and Peng, Sheng-Lin and Zhang, Hua and Weng, Li-Bo and Xu, Hui},
  title = {A biosensor based on graphene nanoribbon with nanopores: a first-principles devices-design},
  journal = {Chinese Physics B},
  year = {2011},
  volume = {20},
  number = {5},
  pages = {058504},
  doi = {http://dx.doi.org/10.1088/1674-1056/20/5/058504}
}
    Song Jiuxu, Yang Yintang, Liu Hongxia & Guo Lixin Negative differential resistance in an (8,0) carbon/boron nitride nanotube heterojunction

    [Abstract] [BibTeX]

    		 2011 Journal of Semiconductors
    Vol. 32(4), 042003     		 DOI URL 
    Abstract: Using the method combined non-equilibrium Green's function with density functional theory, the electronic transport properties of an (8, 0) carbon/boron nitride nanotube heterojunction coupled to Au electrodes were investigated. In the current voltage characteristic of the heterojunction, negative differential resistance was found under positive and negative bias, which is the variation of the localization for corresponding molecular orbital caused by the applied bias voltage. These results are meaningful to modeling and simulating on related electronic devices.
    Keywords: ATK; Application; nanotubes; NDR; negative differential resistance
    Area: nanotubes
    BibTeX: 
    @article{Jiuxu2011,
  author = {Song Jiuxu and Yang Yintang and Liu Hongxia and Guo Lixin},
  title = {Negative differential resistance in an (8,0) carbon/boron nitride nanotube heterojunction},
  journal = {Journal of Semiconductors},
  year = {2011},
  volume = {32},
  number = {4},
  pages = {042003},
  url = {http://stacks.iop.org/1674-4926/32/i=4/a=042003},
  doi = {http://dx.doi.org/10.1088/1674-4926/32/4/042003}
}
    Manabu Kiguchi, Takuya Takahashi, Yuta Takahashi, Yoshihiro Yamauchi, Takashi Murase, Makoto Fujita, Tomofumi Tada & Satoshi Watanabe Electron Transport through Single Molecules Comprising Aromatic Stacks Enclosed in Self-Assembled Cages

    [Abstract] [BibTeX]

    		 2011 Angewandte Chemie
    Vol. 123(25), 5826-5829     		 DOI  
    Abstract: Der Elektronentransport entlang eines pi-Stapels zwischen Nanolücken-Goldelektroden wurde mit STM gemessen. Selbstorganisierte Koordinationskäfige, die pi-gestapelte aromatische Moleküle enthalten, sind leitfähig, der leere Käfig dagegen nicht.

    [Electron transport along a pi-chain between nano gap gold electrodes were measured with STM. Self-organized coordination cages, which contain the pi-stacked molecules, are conducting, while the empty cages are not.]
    Keywords: single molecular studies; electron transfer; molecular electronics; nanogap electrode; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Kiguchi2011,
  author = {Kiguchi, Manabu and Takahashi, Takuya and Takahashi, Yuta and Yamauchi, Yoshihiro and Murase, Takashi and Fujita, Makoto and Tada, Tomofumi and Watanabe, Satoshi},
  title = {Electron Transport through Single Molecules Comprising Aromatic Stacks Enclosed in Self-Assembled Cages},
  journal = {Angewandte Chemie},
  publisher = {WILEY-VCH Verlag},
  year = {2011},
  volume = {123},
  number = {25},
  pages = {5826--5829},
  doi = {http://dx.doi.org/10.1002/ange.201100431}
}
    Yanwei Li, Jinhuan Yao, Shengkui Zhong & Zhengguang Zou Theoretical investigations on the orientational dependence of electron transport through porphyrin molecular wire

    [Abstract] [BibTeX]

    		 2011 Current Applied Physics
    Vol. 11, 1349-1353     		 DOI  
    Abstract: The effect of molecular orientation on the electron transport behavior of single porphyrin sandwiched between two gold (111) electrodes is investigated by density functional theory calculations combined with non-equilibrium Green's function method. The results show that the porphyrin with parallel connection to gold (111) electrodes is more conductive than the porphyrin with diagonal connection to gold (111) electrodes. The mechanism of the difference of electron transport for these two molecular junctions is analyzed from the transmission spectra and the molecular projected self-consistent Hamiltonian states. It is found that the intrinsic nature of the molecule, such as the p-conjugated framework and the strength of moleculeeelectrode coupling, are the essential reason for generating this difference of electron transport for the two molecular systems.
    Keywords: electron transport; porphyrin; non-equilibrium Green's function; molecular electronics; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Li2011b,
  author = {Yanwei Li and Jinhuan Yao and Shengkui Zhong and Zhengguang Zou},
  title = {Theoretical investigations on the orientational dependence of electron transport through porphyrin molecular wire},
  journal = {Current Applied Physics},
  year = {2011},
  volume = {11},
  pages = {1349-1353},
  doi = {http://dx.doi.org/10.1016/j.cap.2011.04.001}
}
    An Liping & Liu Nianhua First-principles study on transport properties of zigzag graphene nanoribbon with different spin-configurations

    [Abstract] [BibTeX]

    		 2011 Journal of Semiconductors
    Vol. 32(5), 052001     		 DOI  
    Abstract: The current-voltage (I-V) characteristics and the transmission spectra of zigzag graphene nanoribbon with different spin-configurations are investigated by using first-principles calculations. It is shown that the I-V curves and transmission spectra strongly depend on the spin-configurations of the two sides of the ribbon. For the spin-parallel configuration structure, the curve is linear under lower bias voltage; for the spin-antiparallel configuration structure, there is a strong spin-polarization-dependent transmission which implies that the ribbon can be used as a spin filter; while for other spin-configuration structures, the curve has the characteristics of a semiconductor. It is found that there is a large magneto-resistance (MR) when the bias voltage is small. The impurity in the central scattering region significantly influences the spin-dependent current and the spin filter efficiency, which may lead the large MR to disappear.
    Keywords: ATK; Application; graphene; magneto-resistance; spin filter;
    Area: graphene; spin
    BibTeX: 
    @article{Liping2011,
  author = {An Liping and Liu Nianhua},
  title = {First-principles study on transport properties of zigzag graphene nanoribbon with different spin-configurations},
  journal = {Journal of Semiconductors},
  year = {2011},
  volume = {32},
  number = {5},
  pages = {052001},
  doi = {http://dx.doi.org/10.1088/1674-4926/32/5/052001}
}
    Guo-Ying Tu, Da-Peng Guo, Bing-Rui Li & Hao-Li Zhang Transport properties and mechanism of C60 coupled to carbon nanotube electrode

    [Abstract] [BibTeX]

    		 2011 Physica B: Condensed Matter
    Vol. 406(11), 2138 - 2142     		 DOI URL 
    Abstract: By applying non-equilibrium Green's functions in combination with density-functional theory, we investigate electronic transport properties of C60 coupled to carbon nanotubes and Li electrodes. The results show that electronic transport properties of CNT-C60-CNT and Li-C60-Li systems are completely different. Nonlinear I-V characteristic, varistor-type behavior and negative differential resistance (NDR) phenomenon are observed when electrodes are carbon nanotubes. We discuss the mechanism of I-V characteristics of CNT-C60-CNT systems in details. Our results suggest conductance, energy level of Frontier molecular orbitals, energy gap between HOMO and LUMO, the coupling between molecular orbitals and electrodes are all playing critical roles in electronic transport properties.
    Keywords: Transport properties; ATK; Application; fullerene; C60; carbon nanotubes; negative differential resistance; NDR; CNT
    Area: nanotubes; fullerenes
    BibTeX: 
    @article{Tu2011,
  author = {Guo-Ying Tu and Da-Peng Guo and Bing-Rui Li and Hao-Li Zhang},
  title = {Transport properties and mechanism of C60 coupled to carbon nanotube electrode},
  journal = {Physica B: Condensed Matter},
  year = {2011},
  volume = {406},
  number = {11},
  pages = {2138 - 2142},
  url = {http://www.sciencedirect.com/science/article/pii/S0921452611002250},
  doi = {http://dx.doi.org/10.1016/j.physb.2011.03.016}
}
    Cai Juan Xia, Ying Tang Zhang & Xue Jun Zai Effects of Different Metal-Molecule Interface Conformations on the Electronic Transport in Molecular Junctions

    [Abstract] [BibTeX]

    		 2011 Materials Science Forum
    Vol. 663-665, 588-591     		 DOI  
    Abstract: Based on nonequilibrium Green's function and first-principles calculation, we investigate the electronic transport of borazine molecule with different metal-molecule interface conformations, namely bridge and top site. The motivation is the variable situations that may arise in break junction experiments. Numerical results show that the current will be increased with the different adsorption sites; especially the enhancement of current is more obvious when molecule is located at the bridge site. Furthermore, a negative differential resistance under applied bias can be observed when the molecule is located at the top site. The mechanism of negative differential resistance is mainly induced by the resonance peak around the Fermi energy in top adsorption site.
    Keywords: Density Functional Theory (DFT); Electronic Transport; Interface Conformation; Negative Differential Resistance; Nonequilibrium Green's Function; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011a,
  author = {Xia, Cai Juan and Zhang, Ying Tang and Zai, Xue Jun},
  title = {Effects of Different Metal-Molecule Interface Conformations on the Electronic Transport in Molecular Junctions},
  journal = {Materials Science Forum},
  year = {2011},
  volume = {663-665},
  pages = {588-591},
  doi = {http://dx.doi.org/10.4028/www.scientific.net/MSF.663-665.588}
}
    Cai Juan Xia, Han Chen Liu & Ying Tang Zhang The Quantum Length Dependence of Conductance in Molecular Device: An Ab Initio Study

    [Abstract] [BibTeX]

    		 2011 Materials Science Forum
    Vol. 663-665, 519-522     		 DOI  
    Abstract: By applying nonequilibrium Green's function formalism combined first-principles density functional theory, we investigate the electronic transport properties of thiophene and furan molecules with different quantum length. the influence of HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the electronic transport through the molecular device are discussed in detail. The results show that the transport behaviors are determined by the distinct electronic structures of the molecular compounds. the length dependence of molecular conductance exhibits its diversity for different molecules.
    Keywords: Density Functional Theory (DFT); Electronic Transport; Nonequilibrium Green's Function; Quantum Length; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011f,
  author = {Xia, Cai Juan and Liu, Han Chen and Zhang, Ying Tang},
  title = {The Quantum Length Dependence of Conductance in Molecular Device: An Ab Initio Study},
  journal = {Materials Science Forum},
  year = {2011},
  volume = {663-665},
  pages = {519-522},
  doi = {http://dx.doi.org/10.4028/www.scientific.net/MSF.663-665.519}
}
    Cai-Juan Xia, De-Sheng Liu, Han-Chen Liu & Xue-Jun Zhai Large negative differential resistance in a molecular device with asymmetric contact geometries: A first-principles study

    [Abstract] [BibTeX]

    		 2011 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 43(8), 1518 - 1521     		 DOI URL 
    Abstract: We report a first-principles study of electronic transport properties and negative differential resistance (NDR) in a single molecular device consisting of a pyrene-based molecule sandwiched between two gold electrodes with different contact geometries. The results show that the electronic transport properties are strongly dependent on the contact geometry. The transmission coefficients and spatial distributions of molecular orbitals under various external biases voltage are analyzed, and it suggests that the asymmetry of the coupling between the molecule and the electrodes with external bias leads to NDR.
    Keywords: ATK; Application; molecular electronics; negative differential resistance; NDR; contact geometry;
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011g,
  author = {Cai-Juan Xia and De-Sheng Liu and Han-Chen Liu and Xue-Jun Zhai},
  title = {Large negative differential resistance in a molecular device with asymmetric contact geometries: A first-principles study},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2011},
  volume = {43},
  number = {8},
  pages = {1518 - 1521},
  url = {http://www.sciencedirect.com/science/article/pii/S1386947711001330},
  doi = {http://dx.doi.org/10.1016/j.physe.2011.04.020}
}
    G P Zhang, X W Fang, Y X Yao, C Z Wang, Z J Ding & K M Ho Electronic structure and transport of a carbon chain between graphene nanoribbon leads

    [Abstract] [BibTeX]

    		 2011 Journal of Physics: Condensed Matter
    Vol. 23(2), 025302     		 DOI URL 
    Abstract: The electronic structure and transport property of a carbon chain between two graphene nanoribbon leads are studied using an ab initio tight-binding (TB) model and Landauer's formalism combined with a non-equilibrium Green's function. The TB Hamiltonian and overlap matrices are extracted from first-principles density functional calculations through the quasi-atomic minimal basis orbital scheme. The accuracy of the TB model is demonstrated by comparing the electronic structure from the TB model with that from first-principles density functional theory. The results of electronic transport on a carbon atomic chain connected to armchair and zigzag graphene ribbon leads, such as different transport characters near the Fermi level and at most one quantized conductance, reveal the effect of the electronic structure of the leads and the scattering from the atomic chain. In addition, bond length alternation and an interesting transmission resonance are observed in the atomic chain connected to zigzag graphene ribbon leads. Our approach provides a promising route to quantitative investigation of both the electronic structure and transport property of large systems.
    Keywords: ATK; Application; graphene; carbon chain;
    Area: graphene
    BibTeX: 
    @article{Zhang2011b,
  author = {G P Zhang and X W Fang and Y X Yao and C Z Wang and Z J Ding and K M Ho},
  title = {Electronic structure and transport of a carbon chain between graphene nanoribbon leads},
  journal = {Journal of Physics: Condensed Matter},
  year = {2011},
  volume = {23},
  number = {2},
  pages = {025302},
  url = {http://stacks.iop.org/0953-8984/23/i=2/a=025302},
  doi = {http://dx.doi.org/10.1088/0953-8984/23/2/025302}
}
    Anurag Srivastava, Neha Tyagi & R.K. Singh Structural and electronic properties of lead nanowires: Ab-initio study

    [Abstract] [BibTeX]

    		 2011 Materials Chemistry and Physics
    Vol. 127(3), 489 - 494     		 DOI URL 
    Abstract: Ab-initio self-consistent study has been performed to analyze the stability of lead nanowires in its six stable configurations like linear, zigzag, triangular, ladder, square and dumbbell. In the present study, the lowest energy structures have been analyzed under the revised Perdew-Burke-Ernzerhof (revPBE) parameterization of generalized gradient approximation (GGA) potential. The two-atom zigzag shaped atomic configuration with highest binding energy and lowest total energy has been confirmed as the most stable structure out of the six atomic configurations. The electronic band structure and density of states have been discussed in detail with a remarkable observation in case of three-atom triangular lead nanowire having a very small band gap while other configurations are found to be metallic. Bulk modulus, pressure derivatives and lattice parameters for different lead nanowires have also been computed and discussed.
    Keywords: Metals; nanostructures; ab initio calculations; computer modeling and simulation; computational techniques; band-structure; ATK; Application; nanowires
    Area: nanowires
    BibTeX: 
    @article{Srivastava2011,
  author = {Anurag Srivastava and Neha Tyagi and R.K. Singh},
  title = {Structural and electronic properties of lead nanowires: Ab-initio study},
  journal = {Materials Chemistry and Physics},
  year = {2011},
  volume = {127},
  number = {3},
  pages = {489 - 494},
  url = {http://www.sciencedirect.com/science/article/pii/S0254058411001556},
  doi = {http://dx.doi.org/10.1016/j.matchemphys.2011.02.044}
}
    K. Stokbro, J. Taylor, M. Brandbyge & H. Guo Ab-initio Non-Equilibrium Green's Function Formalism for Calculating Electron Transport in Molecular Devices

    [Abstract] [BibTeX]

    		 2005
    Vol. 680Introducing Molecular Electronics, 117-151     		 DOI  
    Abstract: The purpose of this chapter is to give a general reader an introduction to the Non Equilibrium Greens Function (NEGF) method for first principles modeling of current-voltage characteristics of molecular electronics devices. The molecular device is modeled on the atomic level, and we will use Density Functional Theory (DFT) to describe the electronic structure of the system. We will give a detailed description of all the steps involved in order to calculate the electron current. The steps involved are dividing the system into electrode and scattering region, determining the one-electron DFT Hamiltonian, setting up the NEGF, determining the charge density, and calculating the effective potential. The procedure sets up a set of selfconsistent equations, which result in an effective one-electron Hamiltonian description of the electron motion. From the one-electron Hamiltonian we can determine the electron current using the Landauer-Büttiger approach.
    Keywords: ATK; Background; Review; Application
    Area: molecular electronics
    BibTeX: 
    @incollection{Stokbro2005,
  author = {Stokbro, K. and Taylor, J. and Brandbyge, M. and Guo, H.},
  title = {Ab-initio Non-Equilibrium Green's Function Formalism for Calculating Electron Transport in Molecular Devices},
  booktitle = {Introducing Molecular Electronics},
  publisher = {Springer Berlin / Heidelberg},
  year = {2005},
  volume = {680},
  pages = {117-151},
  doi = {http://dx.doi.org/10.1007/3-540-31514-4_5}
}
    Yuta Tsuji, Aleksandar Staykov & Kazunari Yoshizawa Orbital Views of Molecular Conductance Perturbed by Anchor Units

    [Abstract] [BibTeX]

    		 2011 Journal of the American Chemical Society
    Vol. 133(15), 5955-5965     		 DOI URL 
    Abstract: Site-specific electron transport phenomena through benzene and benzenedithiol derivatives are discussed on the basis of a qualitative Hückel molecular orbital analysis for better understanding of the effect of anchoring sulfur atoms. A recent work for the orbital control of electron transport through aromatic hydrocarbons provided an important concept for the design of high-conductance connections of a molecule with anchoring atoms. In this work the origin of the frontier orbitals of benzenedithiol derivatives, the effect of the sulfur atoms on the orbitals and on the electron transport properties, and the applicability of the theoretical concept on aromatic hydrocarbons with the anchoring units are studied. The results demonstrate that the orbital view predictions are applicable to molecules perturbed by the anchoring units. The electron transport properties of benzene are found to be qualitatively consistent with those of benzenedithiol with respect to the site dependence. To verify the result of the Hückel molecular orbital calculations, fragment molecular orbital analyses with the extended Hückel molecular orbital theory and electron transport calculations with density functional theory are performed. Calculated results are in good agreement with the orbital interaction analysis. The phase, amplitude, and spatial distribution of the frontier orbitals play an essential role in the design of the electron transport properties through aromatic hydrocarbons.
    Keywords: ATK; Application; molecular electronics;
    Area: molecular electronics
    BibTeX: 
    @article{Tsuji2011,
  author = {Tsuji, Yuta and Staykov, Aleksandar and Yoshizawa, Kazunari},
  title = {Orbital Views of Molecular Conductance Perturbed by Anchor Units},
  journal = {Journal of the American Chemical Society},
  year = {2011},
  volume = {133},
  number = {15},
  pages = {5955-5965},
  url = {http://pubs.acs.org/doi/abs/10.1021/ja111021e},
  doi = {http://dx.doi.org/10.1021/ja111021e}
}
    Z L Zhang, Y P Chen, Y E Xie, M Zhang & J X Zhong Spin-polarized transport properties of Fe atomic chain adsorbed on zigzag graphene nanoribbons

    [Abstract] [BibTeX]

    		 2011 Journal of Physics D: Applied Physics
    Vol. 44(21), 215403     		 DOI URL 
    Abstract: The spin-polarized transport properties of Fe atomic chain adsorbed on zigzag graphene nanoribbons (ZGNRs) are investigated using the density-functional theory in combination with the nonequilibrium Green's function method. We find that the Fe chain has drastic effects on spin-polarized transport properties of ZGNRs compared with a single Fe atom adsorbed on the ZGNRs. When the Fe chain is adsorbed on the centre of the ZGNR, the original semiconductor transforms into metal, showing a very wide range of spin-polarized transport. Particularly, the spin polarization around the Fermi level is up to 100%. This is because the adsorbed Fe chain not only induces many localized states but also has effects on the edge states of ZGNR, which can effectively modulate the spin-polarized transports. The spin polarization of ZGNRs is sensitive to the adsorption site of the Fe chain. When the Fe chain is adsorbed on the edge of ZGNR, the spin degeneracy of conductance is completely broken. The spin polarization is found to be more pronounced because the edge state of one edge is destroyed by the additional Fe chain. These results have direct implications for the control of the spin-dependent conductance in ZGNRs with the adsorption of Fe chains.
    Keywords: ATK; Application; graphene; spin polarization;
    Area: graphene; spin
    BibTeX: 
    @article{Zhang2011a,
  author = {Z L Zhang and Y P Chen and Y E Xie and M Zhang and J X Zhong},
  title = {Spin-polarized transport properties of Fe atomic chain adsorbed on zigzag graphene nanoribbons},
  journal = {Journal of Physics D: Applied Physics},
  year = {2011},
  volume = {44},
  number = {21},
  pages = {215403},
  url = {http://stacks.iop.org/0022-3727/44/i=21/a=215403},
  doi = {http://dx.doi.org/10.1088/0022-3727/44/21/215403}
}
    Y.D. Guo, X.H. Yan & Y. Xiao Multiple negative differential resistance and the modulation in a nanotubelike fullerene D[sub 5h](1)-C[sub 90]

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 98(16), 163107     		 DOI URL 
    Abstract: We have preformed a first-principle calculation on the electronic transport properties of a recently synthesized nanotubelike fullerene D5h(1)-C90. One finds three negative differential resistance regions in the I-V curve, which could be modulated by gate voltage and contact configuration. Further analysis showed that, the charge transfer and molecule-electrode coupling, induced by both bias and gate voltages, are responsible for the observed phenomena.
    Keywords: ab initio calculations; charge transfer states; density functional theory; electrical contacts; electronic structure; fullerenes; negative resistance; ATK; Application
    Area: fullerenes
    BibTeX: 
    @article{Guo2011,
  author = {Y. D. Guo and X. H. Yan and Y. Xiao},
  title = {Multiple negative differential resistance and the modulation in a nanotubelike fullerene D[sub 5h](1)-C[sub 90]},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {98},
  number = {16},
  pages = {163107},
  url = {http://link.aip.org/link/?APL/98/163107/1},
  doi = {http://dx.doi.org/10.1063/1.3582238}
}
    M.L. Hu, Zhizhou Yu, K.W. Zhang, L.Z. Sun & J.X. Zhong Tunneling Magnetoresistance of Bilayer Hexagonal Boron Nitride and Its Linear Response to External Uniaxial Strain

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(16), 8260-8264     		 DOI  
    Abstract: Using density functional theory and nonequilibrium Green's function method, we investigate the tunneling magnetoresistance (TMR) of the magnetotunnel junctions (MTJs) based on bilayer hexagonal boron nitride and its response to external uniaxial strain. The TMR ratio increases linearly with the increasing uniaxial strain because the increasing uniaxial strain reduces the bandgap of bilayer hexagonal boron nitride gradually. Interestingly, the TMR ratio exceeds 95% when the uniaxial strain increases to 2.51%, which is close to that of the perfect spin filter. Our results indicate that the bilayer hexagonal boron nitride is a promising candidate for the spacer of MTJs. Moreover, its TMR ratio can be linearly modulated by external uniaxial strain.
    Keywords: ATK; Application; boron nitride; tunneling magnetoresistance; TMR; strain; magnetic tunnel junction; MTJ; spin
    Area: interfaces; spin; nvm
    BibTeX: 
    @article{Hu2011,
  author = {Hu, M. L. and Yu, Zhizhou and Zhang, K. W. and Sun, L. Z. and Zhong, J. X.},
  title = {Tunneling Magnetoresistance of Bilayer Hexagonal Boron Nitride and Its Linear Response to External Uniaxial Strain},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {115},
  number = {16},
  pages = {8260--8264},
  doi = {http://dx.doi.org/10.1021/jp109971r}
}
    Yutaka Ie, Tomoya Hirose, Hisao Nakamura, Manabu Kiguchi, Noriaki Takagi, Maki Kawai & Yoshio Aso Nature of Electron Transport by Pyridine-Based Tripodal Anchors: Potential for Robust and Conductive Single-Molecule Junctions with Gold Electrodes

    [Abstract] [BibTeX]

    		 2011 Journal of the American Chemical Society
    Vol. 133(9), 3014-3022     		 DOI URL 
    Abstract: We have designed and synthesized a pyridine-based tripodal anchor unit to construct a single-molecule junction with a gold electrode. The advantage of tripodal anchoring to a gold surface was unambiguously demonstrated by cyclic voltammetry measurements. X-ray photoelectron spectroscopy measurements indicated that the pi orbital of pyridine contributes to the physical adsorption of the tripodal anchor unit to the gold surface. The conductance of a single-molecule junction that consists of the tripodal anchor and diphenyl acetylene was measured by modified scanning tunneling microscope techniques and successfully determined to be 5 ± 1 × 10^-4 G0. Finally, by analyzing the transport mechanism based on ab initio calculations, the participation of the pi orbital of the anchor moieties was predicted. The tripodal structure is expected to form a robust junction, and pyridine is predicted to achieve pi-channel electric transport.
    Keywords: ATK; Application; molecular electronics;
    Area: molecular electronics
    BibTeX: 
    @article{Ie2011,
  author = {Ie, Yutaka and Hirose, Tomoya and Nakamura, Hisao and Kiguchi, Manabu and Takagi, Noriaki and Kawai, Maki and Aso, Yoshio},
  title = {Nature of Electron Transport by Pyridine-Based Tripodal Anchors: Potential for Robust and Conductive Single-Molecule Junctions with Gold Electrodes},
  journal = {Journal of the American Chemical Society},
  year = {2011},
  volume = {133},
  number = {9},
  pages = {3014-3022},
  url = {http://pubs.acs.org/doi/abs/10.1021/ja109577f},
  doi = {http://dx.doi.org/10.1021/ja109577f}
}
    Sang Uck Lee, Rodion V. Belosludov, Hiroshi Mizuseki & Yoshiyuki Kawazoe Electron transport characteristics of organic molecule encapsulated carbon nanotubes

    [Abstract] [BibTeX]

    		 2011 Nanoscale
    Vol. 3(4), 1773-1779     		 DOI  
    Abstract: One-dimensional carbon nanotube (CNT) junctions with interesting device characteristics have been designed by encapsulating p- and n-type organic molecules into CNTs with electrophilic tetracyano-p-quinodimethane (TCNQ) and nucleophilic tetrakis(dimethylamino)ethylene (TDAE) molecules in order to explore the effect of encapsulation of organic molecules and rectifying behaviors of the designed one-dimensional CNT p-n junctions. Our results show that p- and n-type doping of CNTs and their associated charge transfer play an important role in determining the electron transport characteristics and lead to materials with unique properties, p-n junction diode, i.e. Zener-like diode. Furthermore, we show that the operational device characteristics of non-covalently doped CNT junctions originate from the distinct response of intrinsic transmission peaks of pure CNTs according to the type of dopant and the applied bias. We believe that the results give an insight into the design and implementation of various electronic logic functions based on CNTs for applications in the field of nanoelectronics.
    Keywords: ATK; Application; carbon nanotubes; rectification; p-n junction; charge transfer; Zener diode; doping; nanoelectronics
    Area: nanotubes
    BibTeX: 
    @article{Lee2011,
  author = {Lee, Sang Uck and Belosludov, Rodion V. and Mizuseki, Hiroshi and Kawazoe, Yoshiyuki},
  title = {Electron transport characteristics of organic molecule encapsulated carbon nanotubes},
  journal = {Nanoscale},
  publisher = {The Royal Society of Chemistry},
  year = {2011},
  volume = {3},
  number = {4},
  pages = {1773--1779},
  doi = {http://dx.doi.org/10.1039/C0NR00757A}
}
    Linze Li, Rui Qin, Hong Li, Lili Yu, Qihang Liu, Guangfu Luo, Zhengxiang Gao & Jing Lu Functionalized Graphene for High-Performance Two-Dimensional Spintronics Devices

    [Abstract] [BibTeX]

    		 2011 ACS Nano
    Vol. 5(4), 2601-2610     		 DOI URL 
    Abstract: Using first-principles calculations, we explore the possibility of functionalized graphene as a high-performance two-dimensional spintronics device. Graphene functionalized with O on one side and H on the other side in the chair conformation is found to be a ferromagnetic metal with a spin-filter efficiency up to 54% at finite bias. The ground state of graphene semifunctionalized with F in the chair conformation is an antiferromagnetic semiconductor, and we construct a spin-valve device from it by introducing a magnetic field to stabilize its metallic ferromagnetic state. The resulting room-temperature magnetoresistance is up to 2200%, which is 1 order of magnitude larger than the available experimental values.
    Keywords: functionalized graphene; spintronics; spin-filter efficiency; magnetoresistance; first-principles calculations; graphone; graphene; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Li2011a,
  author = {Li, Linze and Qin, Rui and Li, Hong and Yu, Lili and Liu, Qihang and Luo, Guangfu and Gao, Zhengxiang and Lu, Jing},
  title = {Functionalized Graphene for High-Performance Two-Dimensional Spintronics Devices},
  journal = {ACS Nano},
  year = {2011},
  volume = {5},
  number = {4},
  pages = {2601-2610},
  url = {http://pubs.acs.org/doi/abs/10.1021/nn102492g},
  doi = {http://dx.doi.org/10.1021/nn102492g}
}
    Hongmei Liu, Zhenzhen Zhao, Nan Wang, Cui Yu & Jianwei Zhao Can the transition from tunneling to hopping in molecular junctions be predicted by theoretical calculation?

    [Abstract] [BibTeX]

    		 2011 Journal of Computational Chemistry
    Vol. 32(8), 1687-1693     		 DOI  
    Abstract: The electron transport mechanism changes from tunneling to hopping as molecular length increases. To validate the theoretical simulation after the transition point and clarify influence of electronic structures on the transition, we calculated the conductance of a series of conjugated molecules by density functional theory together with the nonequilibrium Green's function. We found that the highest occupied molecular orbital energy level, transmission spectrum, and the reorganization energy are good indicators for the transition of the electron transport mechanism. The calculated resistances of short junctions (<50 Å, before the transition point) are consistent with the experimental result, following the tunneling mechanism. However, the theoretical predication failed for long molecules, indicating the limitation of the theoretical framework of elastic scattering when the electron transport mechanism changes to hopping.
    Keywords: molecular junction; theoretical simulation; electron tunneling; electron hopping; reorganization energy; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Liu2011b,
  author = {Liu, Hongmei and Zhao, Zhenzhen and Wang, Nan and Yu, Cui and Zhao, Jianwei},
  title = {Can the transition from tunneling to hopping in molecular junctions be predicted by theoretical calculation?},
  journal = {Journal of Computational Chemistry},
  publisher = {Wiley Subscription Services, Inc., A Wiley Company},
  year = {2011},
  volume = {32},
  number = {8},
  pages = {1687--1693},
  doi = {http://dx.doi.org/10.1002/jcc.21749}
}
    Cai-Juan Xia, Chang-Feng Fang, Peng Zhao & De-Sheng Liu Effect of torsion angle in 4,4'-biphenyldithiol functionalized molecular junction

    [Abstract] [BibTeX]

    		 2011 International Journal of Modern Physics B
    Vol. 25(5), 699-710     		 DOI  
    Abstract: Based on nonequilibrium Green's function and first-principles calculations, we investigate the electronic transport properties of 4,4'-biphenyldithiol functionalized molecular junction with different torsion angles between two phenyl rings. Numerical results show that torsion angle plays an important role in the conducting behavior of molecular junction. By changing the torsion angle, molecule can exhibit a switching behavior. Especially, when the molecule is functionalized with NO2 side group, it will perform a molecular memory effect. Furthermore, effects of different adsorption positions of sulfur atom on molecular memory are also discussed.
    Keywords: ATK; Application; Torsion angle; side group; electronic transport; molecular memory effect; molecular electronics
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011e,
  author = {Xia, Cai-Juan and Fang, Chang-Feng and Zhao, Peng and Liu, De-Sheng},
  title = {Effect of torsion angle in 4,4'-biphenyldithiol functionalized molecular junction},
  journal = {International Journal of Modern Physics B},
  year = {2011},
  volume = {25},
  number = {5},
  pages = {699-710},
  doi = {http://dx.doi.org/10.1142/S0217979211058213}
}
    Shundong Yuan, Chunlei Dai, Jiena Weng, Qunbo Mei, Qidan Ling, Lianhui Wang & Wei Huang Theoretical Studies of Electron Transport in Thiophene Dimer: Effects of Substituent Group and Heteroatom

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry A
    Vol. 115(17), 4535-4546     		 DOI  
    Abstract: The electron-transport properties of various substituted molecules based on the thiol-ended thiophene dimer (2Th1DT) are investigated through density functional theory (DFT) combined with nonequilibrium Green's function (NEGF) method. The current-voltage (I-V) curves of all the Au/2Th1DT/Au systems in this work display similar steplike features, while their equilibrium conductances show a large difference and some of these I-V curves are asymmetric distinctly. The results reveal the dependence of conductance on the energy level of the substituted 2Th1DT molecules. Rectification ratios are computed to examine the asymmetric properties of the I-V curves. The rectifying behavior in the 2Th1DT molecule containing the amino group close to the molecular end is more prominent than that in the other molecules. The rectifying behavior is analyzed through transmission spectra and molecular projected self-consistent Hamiltonian (MPSH) states. Slight negative differential resistance (NDR) can be observed in some of the systems. The electron-transport properties of 2Th1DT molecules containing different heteroatoms are also investigated. The results indicate that the current in heteroatom-containing molecules is larger than that in their pristine analogues, and lighter heteroatoms are more favorable than heavier heteroatoms for electron transport of the thiophene dimer.
    Keywords: ATK; Application; molecular electronics; rectification; MPSH; NDR; negative differential resistance;
    Area: molecular electronics
    BibTeX: 
    @article{Yuan2011,
  author = {Yuan, Shundong and Dai, Chunlei and Weng, Jiena and Mei, Qunbo and Ling, Qidan and Wang, Lianhui and Huang, Wei},
  title = {Theoretical Studies of Electron Transport in Thiophene Dimer: Effects of Substituent Group and Heteroatom},
  journal = {The Journal of Physical Chemistry A},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {115},
  number = {17},
  pages = {4535--4546},
  doi = {http://dx.doi.org/10.1021/jp201038f}
}
    Jiaxin Zheng, Xin Yan, Lili Yu, Hong Li, Rui Qin, Guangfu Luo, Zhengxiang Gao, Dapeng Yu & Jing Lu Family-Dependent Rectification Characteristics in Ultra-Short Graphene Nanoribbon p-n Junctions

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(17), 8547-8554     		 DOI  
    Abstract: We present the first transport property investigation of a-few-nanometer-long armchair graphene nanoribbon (AGNR) p-n junctions by using first-principles method. Intriguingly, family dependent rectification is observed. To be specific, traditional rectification effect in the forward direction is observed in the AGNR p-n junctions with 3n and 3n+2 widths, whereas reverse rectification effect is observed in the AGNR p-n junctions with 3n+1 width. The analysis of the spatial distribution of molecular projected self-consistent Hamiltonian eigenstates and the projected density of states give an insight into the observed results.
    Keywords: ATK; Application; graphene; p-n junction; rectification; MPSH
    Area: graphene
    BibTeX: 
    @article{Zheng2011,
  author = {Zheng, Jiaxin and Yan, Xin and Yu, Lili and Li, Hong and Qin, Rui and Luo, Guangfu and Gao, Zhengxiang and Yu, Dapeng and Lu, Jing},
  title = {Family-Dependent Rectification Characteristics in Ultra-Short Graphene Nanoribbon p-n Junctions},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {115},
  number = {17},
  pages = {8547--8554},
  doi = {http://dx.doi.org/10.1021/jp200982w}
}
    M. Zhou, Y.Q. Cai, M.G. Zeng, C. Zhang & Y.P. Feng Mn-doped thiolated Au[sub 25] nanoclusters: Atomic configuration, magnetic properties, and a possible high-performance spin filter

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 98(14), 143103     		 DOI URL 
    Abstract: We report an ab inito investigation on the ground-state atomic configuration, electronic structures, magnetic, and spin-dependent transport properties of Mn-doped Au25 nanoclusters protected by thiolate. It is found that the most stable dopant sites are near surfaces, rather than the center position of the nanoparticles. Transport calculations show that high- performance spin filters can be achieved by sandwiching these doped clusters between two nonmagnetic Au electrodes. The nearly perfect spin filtering originates from localized magnetic moments of these clusters that are well protected by ligands from the presence of electrodes.
    Keywords: ab initio calculations; gold; ground states; magnetic moments; manganese; nanomagnetics; nanoparticles; spin dynamics; spin polarised transport; ATK; Application
    Area: molecular electronics; spin
    BibTeX: 
    @article{Zhou2011,
  author = {M. Zhou and Y. Q. Cai and M. G. Zeng and C. Zhang and Y. P. Feng},
  title = {Mn-doped thiolated Au[sub 25] nanoclusters: Atomic configuration, magnetic properties, and a possible high-performance spin filter},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {98},
  number = {14},
  pages = {143103},
  url = {http://link.aip.org/link/?APL/98/143103/1},
  doi = {http://dx.doi.org/10.1063/1.3575203}
}
    Hui Fang, Ru-Zhi Wang, Si-Ying Chen, Mi Yan, Xue-Mei Song & Bo Wang Strain-induced negative differential resistance in armchair-edge graphene nanoribbons

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 98(8), 082108     		 DOI  
    Abstract: The transport properties of graphene strips under tensile strain have been theoretically investigated. For the armchair-edge graphene nanoribbons (GNRs) with width N = 3m-1, the additional negative differential resistance (NDR) undergoes a process from occurring to enhancement and then disappearance with increasing tensile strain. The changes in the additional NDR may be originated from the suppression of strain-mediated channel states for the variations in degenerate energy bands near Fermi level. The strain-induced NDR behaviors of the GNRs present the possibility of the potential applications in electromechanical nanodevices such as stress-controlled Goto pair for digital signal restoration.
    Keywords: ATK; Application; ATK-SE; Fermi level; internal stresses; nanostructured materials; tensile strength; graphene nanoribbon; negative differential resistance; NDR;
    Area: graphene
    BibTeX: 
    @article{Fang2011,
  author = {Fang, Hui and Wang, Ru-Zhi and Chen, Si-Ying and Yan, Mi and Song, Xue-Mei and Wang, Bo},
  title = {Strain-induced negative differential resistance in armchair-edge graphene nanoribbons},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {98},
  number = {8},
  pages = {082108},
  doi = {http://dx.doi.org/10.1063/1.3556637}
}
    Yongqing Cai, Miao Zhou, Minggang Zeng, Chun Zhang & Yuan Ping Feng Adsorbate and defect effects on electronic and transport properties of gold nanotubes

    [Abstract] [BibTeX]

    		 2011 Nanotechnology
    Vol. 22(21), 215702     		 DOI URL 
    Abstract: First-principles calculations have been performed to study the effects of adsorbates (CO molecules and O atoms) and defects on electronic structures and transport properties of Au nanotubes (Au(5, 3) and Au(5, 5)). For CO adsorption, various adsorption sites of CO on the Au tubes were considered. The vibrational frequency of the CO molecule was found to be very different for two nearly degenerate stable adsorption configurations of Au(5, 3), implying the possibility of distinguishing these two configurations via measuring the vibrational frequency of CO in experiments. After CO adsorption, the conductance of Au(5, 3) decreases by 0.9 G 0 and the conductance of Au(5, 5) decreases by approximately 0.5 G 0 . For O-adsorbed Au tubes, O atoms strongly interact with Au tubes, leading to around 2 G 0 of drop in conductance for both Au tubes. These results may have implications for Au-tube-based chemical sensing. When a monovacancy defect is present, we found that, for both tubes, the conductance decreases by around 1 G 0 . Another type of defect arising from the adhesion of one Au atom is also considered. For this case, it is found that, for the Au(5, 3) tube, the defect decreases the conductance by nearly 1 G 0 , whereas for Au(5, 5), the decrease in conductance is only 0.3 G 0 .
    Keywords: ATK; Application; gold nanotube; adsorbed molecules; vacancies
    Area: nanotubes
    BibTeX: 
    @article{Cai2011,
  author = {Yongqing Cai and Miao Zhou and Minggang Zeng and Chun Zhang and Yuan Ping Feng},
  title = {Adsorbate and defect effects on electronic and transport properties of gold nanotubes},
  journal = {Nanotechnology},
  year = {2011},
  volume = {22},
  number = {21},
  pages = {215702},
  url = {http://stacks.iop.org/0957-4484/22/i=21/a=215702},
  doi = {http://dx.doi.org/10.1088/0957-4484/22/21/215702}
}
    Qihang Liu, Lili Yu, Hong Li, Rui Qin, Zhou Jing, Jiaxin Zheng, Zhengxiang Gao & Jing Lu All-Metallic High-Performance Field Effect Transistor Based on Telescoping Carbon Nanotubes: An ab Initio Study

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(14), 6933-6938     		 DOI URL 
    Abstract: It has been well established that the electrical resistance of metal is insensitive to gate voltage and unsuitable for making field effect transistors. However, we find that telescoping pristine double-walled metallic carbon nanotubes are extremely sensitive to gate voltage with an on/off ratio up to 10,000 based on the first principles quantum transport calculations. This remarkable feature is closely related to the antiresonances in the transmission spectra. Besides, robust negative differential resistance effects are also found in the same device.
    Keywords: ATK; Application; field effect transistor; nanotube; NDR; negative differential resistance; telescoping tubes;
    Area: nanotubes
    BibTeX: 
    @article{Liu2011a,
  author = {Liu, Qihang and Yu, Lili and Li, Hong and Qin, Rui and Jing, Zhou and Zheng, Jiaxin and Gao, Zhengxiang and Lu, Jing},
  title = {All-Metallic High-Performance Field Effect Transistor Based on Telescoping Carbon Nanotubes: An ab Initio Study},
  journal = {The Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  number = {14},
  pages = {6933-6938},
  url = {http://pubs.acs.org/doi/abs/10.1021/jp112285t},
  doi = {http://dx.doi.org/10.1021/jp112285t}
}
    CaiJuan Xia, DeSheng Liu & HanChen Liu A first-principles study of dihydroazulene as a possible optical molecular switch

    [Abstract] [BibTeX]

    		 2011 SCIENCE CHINA Physics, Mechanics & Astronomy
    Vol. 54(3), 437-441     		 DOI  
    Abstract: By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of the dihydroazulene optical molecular switch. Three kinds of adsorption sites including the hollow, bridge and top sites are studied. The two forms of this molecule, namely the open form and the closed form, can reversibly switch from each other upon photoexcitation. Their transmission spectra are remarkably distinctive. Theoretical results show that the current of the closed form is always significantly larger than that of the open form for all three adsorption sites, which promises this system as possibly one of the good candidates for optical switches due to its unique advantage, and which may have some potential applications in the future molecular circuit.
    Keywords: molecular electronics; ATK; Application; molecular switch; nonequilibrium Green's function; electronic transport; density functional theory
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011b,
  author = {Xia, CaiJuan and Liu, DeSheng and Liu, HanChen},
  title = {A first-principles study of dihydroazulene as a possible optical molecular switch},
  journal = {SCIENCE CHINA Physics, Mechanics & Astronomy},
  publisher = {Science China Press, co-published with Springer},
  year = {2011},
  volume = {54},
  number = {3},
  pages = {437--441},
  doi = {http://dx.doi.org/10.1007/s11433-010-4233-5}
}
    CaiJuan Xia, HanChen Liu & QiuPing Wang An Ab Initio Study on Negative Differential Resistance in Pyrrole Trimer Molecular Device

    [Abstract] [BibTeX]

    		 2011 Advanced Materials Research
    Vol. 152-153, 931-934     		 DOI  
    Abstract: The electronic transport properties of pyrrole trimer sandwiched between two electrodes are investigated by using nonequilibrium Green's function formalism combined first-principles density functional theory. Theoretical results show that the system manifests negative differential resistance (NDR) behavior. A detailed analysis of the origin of negative differential resistance has been given by observing the shift in transmission resonance peak across the bias window with varying bias voltage.
    Keywords: ATK; Application; molecular device; NDR; negative differential resistance;
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011c,
  author = {Xia, CaiJuan and Liu, HanChen and Wang, QiuPing},
  title = {An Ab Initio Study on Negative Differential Resistance in Pyrrole Trimer Molecular Device},
  journal = {Advanced Materials Research},
  year = {2011},
  volume = {152-153},
  pages = {931-934},
  doi = {http://dx.doi.org/10.4028/www.scientific.net/AMR.152-153.931}
}
    CaiJuan Xia, HanChen Liu & ChangFeng Fang The I-V Characteristics of the 3,3',5',5-Tetra-Tert-Butyl-Azobenzene Optical Molecular Switch: A First-Principles Study

    [Abstract] [BibTeX]

    		 2011 Advanced Materials Research
    Vol. 152-153, 839-842     		 DOI  
    Abstract: By applying nonequilibrium Green's function formalism combined first-principles density functional theory, we investigate the electronic transport properties of 3,3',5,5'-Tetra-tert-butyl-azobenzene(meta-TBA) optical molecular switch. This molecular switch comprises a meta-TBA molecule with the trans and cis forms, which can be reversed from one structure to another one upon photoexcitation. The influence of HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the electronic transport through the molecular device are discussed in detail. Theoretical results show that there is a large current ratio in bias window, which suggests that this system can be one of good candidates for optical switches due to this unique advantage, and have real applications in the molecular circuit.
    Keywords: ATK; Application; molecular switch; NDR; negative differential resistance; optical switch
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011d,
  author = {Xia, CaiJuan and Liu, HanChen and Fang, ChangFeng},
  title = {The I-V Characteristics of the 3,3',5',5-Tetra-Tert-Butyl-Azobenzene Optical Molecular Switch: A First-Principles Study},
  journal = {Advanced Materials Research},
  year = {2011},
  volume = {152-153},
  pages = {839-842},
  doi = {http://dx.doi.org/10.4028/www.scientific.net/AMR.152-153.839}
}
    Guiling Zhang, Dong Li, Yan Shang, Hui Zhang, Miao Sun, Bo Liu & Zesheng Li Transport Properties of Double Quantum Dots Formed by Ferrocene Units

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(13), 5257-5264     		 DOI  
    Abstract: Combining nonequilibrium Green's function technique with density functional theory, the transport properties of a series of double quantum dots formed by ferrocene dimers with saturated carbon bridges and saturated silicon bridges, [Fc-(CH2)n]2 and [Fc-(SiH2)n]2 (n = 1,2,3), were comparatively studied. We have found that the type and the length of the bridge group between two adjacent ferrocene units plays an important role in governing the transport property. The negative differential resistance is enhanced with the lengthening of the space linker, i.e., the NDR magnitude follows the sequence of [Fc-(CH2)3]2 > [Fc-(CH2)2]2 > [Fc-CH2]2 and [Fc-(SiH2)3]2 > [Fc-(SiH2)2]2 > [Fc-SiH2]2. For the short bridged systems (n = 1,2), the conductivity of molecules with the carbon linkage is higher than that with the silicon linkage, that is, [Fc-CH2]2 > [Fc-SiH2]2 and [Fc-(CH2)2]2 > [Fc-(SiH2)2]2. In addition, [Fc-SiH2] presents a rectifier effect. The effect of the bridge on the transport property could be interpreted from the bonding, the molecular level state, the transmission spectrum, and the density of states.
    Keywords: ATK; Application; molecular electronics; ferrocene; quantum dots; negative differential resistance; NDR;
    Area: molecular electronics
    BibTeX: 
    @article{Zhang2011,
  author = {Zhang, Guiling and Li, Dong and Shang, Yan and Zhang, Hui and Sun, Miao and Liu, Bo and Li, Zesheng},
  title = {Transport Properties of Double Quantum Dots Formed by Ferrocene Units},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {115},
  number = {13},
  pages = {5257--5264},
  doi = {http://dx.doi.org/10.1021/jp1092064}
}
    Peng Zhao, De-Sheng Liu, Ying Zhang, Pei-Ji Wang & Zhong Zhang Rectifying Properties of a Nitrogen/Boron-Doped Capped-Carbon-Nanotube-Based Molecular Junction

    [Abstract] [BibTeX]

    		 2011 Chinese Physics Letters
    Vol. 28(4), 047301     		 DOI URL 
    Abstract: Based on the non-equilibrium Green's function method and first-principles density functional theory calculations, we investigate the electronic transport properties of a nitrogen/boron-doped capped-single-walled carbon-nanotube-based molecular junction. Obvious rectifying behavior is observed and it is strongly dependent on the doping site. The best rectifying performance can be carried out when the nitrogen/boron atom dopes at a carbon site in the second layer. Moreover, the rectifying performance can be further improved by adjusting the distance between the C 60 nanotube
    Keywords: ATK; Application; capped nanotube; carbon nanotube; rectification
    Area: nanotubes
    BibTeX: 
    @article{Zhao2011b,
  author = {Zhao, Peng and Liu, De-Sheng and Zhang, Ying and Wang, Pei-Ji and Zhang, Zhong},
  title = {Rectifying Properties of a Nitrogen/Boron-Doped Capped-Carbon-Nanotube-Based Molecular Junction},
  journal = {Chinese Physics Letters},
  year = {2011},
  volume = {28},
  number = {4},
  pages = {047301},
  url = {http://stacks.iop.org/0256-307X/28/i=4/a=047301},
  doi = {http://dx.doi.org/10.1088/0256-307X/28/4/047301}
}
    Larkhoon Leem, Ashutosh Srivastava, Shuang Li, Blanka Magyari-Köpe, Giuseppe Iannaccone, James Harris & Gianluca Fiori Multi-scale Simulations of Partially Unzipped CNT Hetero-junction Tunneling Field Effect Transistor

    [Abstract] [BibTeX]

    		 2010 2010 International Electron Devices Meeting - Technical Digest, 32.5.1-32.5.4  DOI  
    Abstract: Band-to-band Tunneling Field Effect Transistors (TFETs) are emerging as a solution to break classical 60mV/dec sub-threshold slope limit of conventional MOSFETs. In this work, we present for the first time multi-scale simulation results of partially unzipped Carbon Nanotube heterojunction TFET. Compared to the CNT and GNR homojunction TFETs, GNR/CNT heterojunction TFETs demonstrate superior sub-threshold region characteristics - 10(4)x smaller I-off, 61% smaller Subthreshold Swing (SS) which lies in the range of 22 similar to 26mV/dec and the I-V ambipolarity is completely eliminated.
    Keywords: MOSFET; carbon nanotubes; field effect transistors; semiconductor heterojunctions; tunnel transistors; tunnelling; heterojunction TFET; I-V ambipolarity; band-to-band tunneling field effect transistors; conventional MOSFET; multiscale simulation; sub-threshold slope limit; subthreshold region characteristics; subthreshold swing; graphene nanoribbon; ATK; Application
    Area: graphene; nanotubes
    BibTeX: 
    @inproceedings{Leem2010,
  author = {Leem, Larkhoon and Srivastava, Ashutosh and Li, Shuang and Magyari-Köpe, Blanka and Iannaccone, Giuseppe and Harris, James and Fiori, Gianluca},
  title = {Multi-scale Simulations of Partially Unzipped CNT Hetero-junction Tunneling Field Effect Transistor},
  booktitle = {2010 International Electron Devices Meeting - Technical Digest},
  publisher = {IEEE, 345 E 47th St, New York, NY 10017 USA},
  year = {2010},
  pages = {32.5.1--32.5.4},
  note = {International Electron Devices Meeting (IEDM), San Francisco, CA, DEC 06-08, 2010},
  doi = {http://dx.doi.org/10.1109/IEDM.2010.5703465}
}
    Xin Luo, Biao Wang & Yue Zheng Tunable Tunneling Electroresistance in Ferroelectric Tunnel Junctions by Mechanical Loads

    [Abstract] [BibTeX]

    		 2011 ACS Nano
    Vol. 5(3), 1649-1656     		 DOI  
    Abstract: Combining nonequilibrium Green function's approach with density functional theory, effects of the applied mechanical loads on polarization, electrostatic potential, and tunneling conductance of a ferroelectric tunneling junction (FTJ) have been investigated. Using the first principle calculations, we show that compressive strains can induce and enhance the polarization in ferroelectric tunnel barriers, and practically achieve ferroelectricity in two unit cell thickness under a -2.2% compressive strain. More importantly, mechanical strains can significantly change the effective electrostatic potential in FTJ and thus control its tunneling conductance, which is defined as giant piezoelectric resistance (GPR) effect. Our calculations indicate that GPR effect is particularly significant near the paraelectric/ferroelectric phase transition, and increases exponentially with the barrier thickness. Furthermore, it is also found that defects of oxygen vacancies and nitrogen doping have little impact on GPR ratio of strained FTJ. Because of its high-sensitivity to external mechanical loads, FTJ with GPR effect should be adequate for applications in agile mechanical sensors, transducers, and other multifunctional devices.
    Keywords: ATK; Application; ferroelectric tunneling junction; giant piezoelectric resistance; conductance; strain; phase transitionferroelectric tunneling junction; giant piezoelectric resistance; conductance; strain; phase transition
    Area: interfaces; semi
    BibTeX: 
    @article{Luo2011,
  author = {Luo, Xin and Wang, Biao and Zheng, Yue},
  title = {Tunable Tunneling Electroresistance in Ferroelectric Tunnel Junctions by Mechanical Loads},
  journal = {ACS Nano},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {5},
  number = {3},
  pages = {1649--1656},
  doi = {http://dx.doi.org/10.1021/nn1031438}
}
    J.B. Pan, Z.H. Zhang, K.H. Ding, X.Q. Deng & C. Guo Current rectification induced by asymmetrical electrode materials in a molecular device

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 98(9), 092102     		 DOI  
    Abstract: Molecular devices are constructed based on a molecule connected into both electrodes with different metal materials, and their transport properties are investigated by the first-principles method. The result shows that such devices can generate two asymmetrical Schottky barriers at contacts; the current rectification thus is created. This rectification is also fully rationalized by the calculated transmission spectra and the spatial distribution of the lowest unoccupied molecular orbital and highest occupied molecular orbital states. Our study suggests that it might be a very important way for both electrodes using different materials to realize a molecular rectification.
    Keywords: ATK; Application; molecular electronics; asymmetrical Schottky barriers; rectification;
    Area: molecular electronics
    BibTeX: 
    @article{Pan2011,
  author = {Pan, J. B. and Zhang, Z. H. and Ding, K. H. and Deng, X. Q. and Guo, C.},
  title = {Current rectification induced by asymmetrical electrode materials in a molecular device},
  journal = {Applied Physics Letters},
  year = {2011},
  volume = {98},
  number = {9},
  pages = {092102},
  doi = {http://dx.doi.org/10.1063/1.3556278}
}
    Zhongchang Wang, Masaki Okude, Mitsuhiro Saito, Susumu Tsukimoto, Akira Ohtomo, Masaru Tsukada, Masashi Kawasaki & Yuichi Ikuhara Dimensionality-driven insulator-metal transition in A-site excess non-stoichiometric perovskites

    [Abstract] [BibTeX]

    		 2010 Nature Communications
    Vol. 1(8), 106     		 DOI  
    Abstract: Coaxing correlated materials to the proximity of the insulator-metal transition region, where electronic wavefunctions transform from localized to itinerant, is currently the subject of intensive research because of the hopes it raises for technological applications and also for its fundamental scientific significance. In general, this tuning is achieved by either chemical doping to introduce charge carriers, or external stimuli to lower the ratio of Coulomb repulsion to bandwidth. In this study, we combine experiment and theory to show that the transition from well-localized insulating states to metallicity in a Ruddlesden-Popper series, La(0.5)Sr(n+1-0.5)Ti(n)O(3n+1), is driven by intercalating an intrinsically insulating SrTiO3 unit, in structural terms, by dimensionality n. This unconventional strategy, which can be understood upon a complex interplay between electron-phonon coupling and electron correlations, opens up a new avenue to obtain metallicity or even superconductivity in oxide superlattices that are normally expected to be insulators.
    Keywords: ATK; Application; metal-insulator junction; superconductivity; metallicity; oxide superlattices; SrTiO3;
    Area: interfaces; semi; nvm
    BibTeX: 
    @article{Wang2010d,
  author = {Wang, Zhongchang and Okude, Masaki and Saito, Mitsuhiro and Tsukimoto, Susumu and Ohtomo, Akira and Tsukada, Masaru and Kawasaki, Masashi and Ikuhara, Yuichi},
  title = {Dimensionality-driven insulator-metal transition in A-site excess non-stoichiometric perovskites},
  journal = {Nature Communications},
  publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
  year = {2010},
  volume = {1},
  number = {8},
  pages = {106},
  doi = {http://dx.doi.org/10.1038/ncomms1111}
}
    Xiaojun Wu, Rulong Zhou, Jinlong Yang & Xiao Cheng Zeng Density-Functional Theory Studies of Step-Kinked Carbon Nanotubes

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(10), 4235-4239     		 DOI  
    Abstract: Using density-functional theory (DFT) methods, we investigate structural, electronic, and transport properties of step-kinked single-walled carbon nanotubes (SWCNT). To devise a sensible model for the joint section of the kinked nanotube, we examine relative stability of two (6,0) carbon-nanotube-based C672 isomers, namely, a carbon nanoring and a carbon hexagonal nanotorus. We find that the hexagonal nanotorus C672 is energetically more favorable than the isomeric nanoring (i.e., circular nanotorus) C672. By use of the kinked section of the hexagonal nanotorus as a model joint, the periodic step-kinked carbon nanotubes can be built. According to the DFT calculation using the hybrid B3LYP functional, we find that introduction of the periodic kinks turns the perfect (5,0) SWCNT with zero band gap ( J. Phys. Chem. Lett. 2010, 1, 2946) into a semiconductor with a band gap 0.76 eV. In contrast, the step-kinked (6,0) SWCNT is still a metal with zero band gap, like the perfect (6,0) SWCNT. We also compare the electronic transport properties of a perfect (5,0) SWCNT with the step-kinked (5,0) SWCNT. The former has a nonzero steplike electron transmission distribution near the Fermi level, while the latter shows some sharp transmission peaks around the Fermi level.
    Keywords: ATK; Application; nanotube; nanotorus; transport properties:
    Area: nanotubes
    BibTeX: 
    @article{Wu2011,
  author = {Wu, Xiaojun and Zhou, Rulong and Yang, Jinlong and Zeng, Xiao Cheng},
  title = {Density-Functional Theory Studies of Step-Kinked Carbon Nanotubes},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {115},
  number = {10},
  pages = {4235--4239},
  doi = {http://dx.doi.org/10.1021/jp110717k}
}
    Minggang Zeng, Lei Shen, Ming Yang, Chun Zhang & Yuanping Feng Feng Charge and spin transport in graphene-based heterostructure

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 98(5), 053101-3     		 DOI  
    Abstract: We investigate electron transport properties of a heterostructure based on zigzag graphene nanoribbon (ZGNR) by first-principles calculations. This heterostructure consists of hydrogen-terminated ZGNR (ZGNR-H) and oxygen-terminated ZGNR (ZGNR-O). We find that both charge and spin transport can be well controlled with the ZGNR-H/ZGNR-O heterostructure. A large charge transmission gap appears near the Fermi energy, and rectification behavior is observed. Moreover, the ZGNR-H/ZGNR-O heterostructure can act as a perfect bipolar spin filter or magnetoresistance device. Our results show that the ZGNR-H/ZGNR-O heterostructure hold promise for combining magnetoelectronics and conventional charge-based electronics.
    Keywords: ab initio calculations; density functional theory; Fermi level; giant magnetoresistance; graphene; Green's function methods; hydrogen; nanostructured materials; oxygen; rectification; ATK; Application; spin
    Area: graphene; spin
    BibTeX: 
    @article{Zeng2011b,
  author = {Zeng, Minggang and Shen, Lei and Yang, Ming and Zhang, Chun and Feng, Yuanping Feng},
  title = {Charge and spin transport in graphene-based heterostructure},
  journal = {Applied Physics Letters},
  year = {2011},
  volume = {98},
  number = {5},
  pages = {053101--3},
  doi = {http://dx.doi.org/10.1063/1.3549154}
}
    Minggang Zeng, Yuanping Feng & Gengchiau Liang Graphene-based Spin Caloritronics

    [Abstract] [BibTeX]

    		 2011 Nano Letters
    Vol. 11(3), 1369-1373     		 DOI  
    Abstract: Thermally induced spin transport in magnetized zigzag graphene nanoribbons (M-ZGNRs) is explored using first-principles calculations. By applying temperature difference between the source and the drain of a M-ZGNR device, spin-up and spin-down currents flowing in opposite directions can be induced. This spin Seebeck effect in M-ZGNRs can be attributed to the asymmetric electron-hole transmission spectra of spin-up and spin-down electrons. Furthermore, these spin currents can be modulated and completely polarized by tuning the back gate voltage. Finally, thermal magnetoresistance of ZGNRs between ground states and magnetized states can reach 104% without an external bias. Our results indicate the possibility of developing graphene-based spin caloritronic devices.
    Keywords: ATK; Application; graphene; spin caloritronics; spintronics; spin Seebeck effect; thermal magnetoresistance effect; thermal spin components
    Area: graphene; spin
    BibTeX: 
    @article{Zeng2011c,
  author = {Zeng, Minggang and Feng, Yuanping and Liang, Gengchiau},
  title = {Graphene-based Spin Caloritronics},
  journal = {Nano Letters},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {11},
  number = {3},
  pages = {1369--1373},
  doi = {http://dx.doi.org/10.1021/nl2000049}
}
    Jing Zhou, Xin Yan, Guangfu Luo, Rui Qin, Hong Li, Jing Lu, Wai Ning Mei & Zhengxiang Gao Structural, Electronic, and Transport Properties of Gd/Eu Atomic Chains Encapsulated in Single-Walled Carbon Nanotubes

    [Abstract] [BibTeX]

    		 2010 The Journal of Physical Chemistry C
    Vol. 114(36), 15347-15353     		 DOI  
    Abstract: Structural, electronic, and transport properties of Gd/Eu atomic chains encapsulated in single-walled carbon nanotubes (SWCNTs) are studied by using first-principles density functional theory and the nonequilibrium Green's function method. We find that the linear single-atom Gd and Eu chains occupy an off-centered position when encapsulated in the (8,0), (10,0), and (6,6) SWCNTs and considerable electrons are transferred from the Gd and Eu chains to the SWCNTs. The resulting composites are all ferromagnetic metals, with the conductivity significantly larger than those of the pristine SWCNTs and the free-standing Gd/Eu linear single-atom atomic chains. The spin polarization of the finite Gd linear single-atom chain at the Fermi level is 67% when encapsulated in the (8,0) SWCNT from the quantum transport calculation.
    Keywords: atomic chains; rare earth elements; carbon nanotubes; electron transfer; ATK; Application; spin
    Area: nanotubes; spin
    BibTeX: 
    @article{Zhou2010b,
  author = {Zhou, Jing and Yan, Xin and Luo, Guangfu and Qin, Rui and Li, Hong and Lu, Jing and Mei, Wai Ning and Gao, Zhengxiang},
  title = {Structural, Electronic, and Transport Properties of Gd/Eu Atomic Chains Encapsulated in Single-Walled Carbon Nanotubes},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2010},
  volume = {114},
  number = {36},
  pages = {15347--15353},
  doi = {http://dx.doi.org/10.1021/jp105274v}
}
    H. Sahin, R.T. Senger & S. Ciraci Spintronic properties of zigzag-edged triangular graphene flakes

    [Abstract] [BibTeX]

    		 2010 Journal of Applied Physics
    Vol. 108(7), 074301-5     		 DOI URL 
    Abstract: We investigate quantum transport properties of triangular graphene flakes with zigzag edges by using first principles calculations. Triangular graphene flakes have large magnetic moments which vary with the number of hydrogen atoms terminating its edge atoms and scale with its size. Electronic transmission and current-voltage characteristics of these flakes, when contacted with metallic electrodes, reveal spin valve and remarkable rectification features. The transition from ferromagnetic to antiferromagnetic state under bias voltage can, however, terminate the spin polarizing effects for specific flakes. Geometry and size dependent transport properties of graphene flakes may be crucial for spintronic nanodevice applications.
    Keywords: ab initio calculations; antiferromagnetic materials; ferromagnetic materials; ferromagnetic-antiferromagnetic transitions; graphene; hydrogen neutral atoms; magnetic moments; magnetoelectronics; spin polarised transport; spin valves; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Sahin2010,
  author = {Sahin, H. and Senger, R. T. and Ciraci, S.},
  title = {Spintronic properties of zigzag-edged triangular graphene flakes},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2010},
  volume = {108},
  number = {7},
  pages = {074301--5},
  url = {http://link.aip.org/link/?JAP/108/074301/1},
  doi = {http://dx.doi.org/10.1063/1.3489919}
}
    Zhenxiang Dai, Argo Nurbawono, Aihua Zhang, Miao Zhou, Yuan Ping Feng, Ghim Wei Ho & Chun Zhang C-doped ZnO nanowires: Electronic structures, magnetic properties, and a possible spintronic device

    [Abstract] [BibTeX]

    		 2011 Journal of Chemical Physics
    Vol. 134(10), 104706-5     		 DOI  
    Abstract: Electronic structures, magnetic properties, and spin-dependent electron transport characteristics of C-doped ZnO nanowires have been investigated via first-principles method based on density functional theory and nonequilibrium techniques of Green's functions. Our calculations show that the doping of carbon atoms in a ZnO nanowire could induce strong magnetic moments in the wire, and the electronic structures as well as the magnetic properties of the system sensitively depend on partial hydrogenation. Based on these findings, we proposed a quasi-1d tunneling magnetic junction made of a partially hydrogenated C-doped ZnO nanowire, which shows a high tunneling magnetoresistance ratio, and could be the building block of a new class of spintronic devices.
    Keywords: ab initio calculations; density functional theory; energy gap; Green's function methods; hydrogenation; II-VI semiconductors; magnetic moments; nanomagnetics; nanowires; semiconductor quantum wires; semimagnetic semiconductors; spin polarised transport; tunnelling magnetoresistance; wide band gap semiconductors; zinc compounds; ATK; Application
    Area: nanowires, spin
    BibTeX: 
    @article{Dai2011,
  author = {Dai, Zhenxiang and Nurbawono, Argo and Zhang, Aihua and Zhou, Miao and Feng, Yuan Ping and Ho, Ghim Wei and Zhang, Chun},
  title = {C-doped ZnO nanowires: Electronic structures, magnetic properties, and a possible spintronic device},
  journal = {Journal of Chemical Physics},
  publisher = {AIP},
  year = {2011},
  volume = {134},
  number = {10},
  pages = {104706--5},
  doi = {http://dx.doi.org/10.1063/1.3562375}
}
    Nengyue Gao, Hongmei Liu, Cui Yu, Nan Wang, Jianwei Zhao & Hongfeng Xie Asymmetric electron transport through a conjugated-saturated hydrocarbon molecular wire

    [Abstract] [BibTeX]

    		 2011 Computational and Theoretical Chemistry
    Vol. 963(1), 55-62     		 DOI URL 
    Abstract: To understand the barrier effect on the asymmetric electron transport, we have employed a series of hybrid molecular junctions composed of conjugated and saturated hydrocarbon chains. The length of molecular wire is fixed, while the ratio of conjugated and saturated chains varies. In each model, the current-voltage characteristics have been studied using the first-principles density functional theory in conjunction with the non-equilibrium Green's function method. We found that the rectification performance is correlated to the barrier length. The mechanism of this phenomenon is related to the asymmetric coupling between the conjugated moiety and the metallic electrode.
    Keywords: Molecular rectification; Electron transport; Molecular junction; Electrode-molecule coupling; Barrier length; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Gao2011,
  author = {Gao, Nengyue and Liu, Hongmei and Yu, Cui and Wang, Nan and Zhao, Jianwei and Xie, Hongfeng},
  title = {Asymmetric electron transport through a conjugated-saturated hydrocarbon molecular wire},
  journal = {Computational and Theoretical Chemistry},
  year = {2011},
  volume = {963},
  number = {1},
  pages = {55--62},
  url = {http://www.sciencedirect.com/science/article/B6KFD-5172701-6/2/5ddfc7eb43ff356153c84d98129a63b1},
  doi = {http://dx.doi.org/10.1016/j.comptc.2010.09.008}
}
    Guomin Ji, Yaxin Zhai, Changfeng Fang, Yuqing Xu, Bin Cui & Desheng Liu The electronic transport properties in C60 molecular devices with different contact distances

    [Abstract] [BibTeX]

    		 2011 Physics Letters A
    Vol. 375(14), 1602-1607     		 DOI URL 
    Abstract: By applying non-equilibrium Green's functions in combination with the density-functional theory, we investigate the transport behavior of molecular devices composed by metal electrode-C60 molecule-metal electrode. Our results show that the electronic transport properties are affected obviously by the different contact distances between the electrodes, and the tunneling current decreases approximately exponentially at a certain bias with the increasing of contact distances. The negative differential resistance is observed and the peak-to-valley ratio can be tuned by different contact distances. The mechanisms of the contact distance effect and the negative differential resistance behavior are proposed.
    Keywords: ATK; Application; Negative differential resistance; NDR; fullerene; molecular electronics; molecular device
    Area: molecular electronics
    BibTeX: 
    @article{Ji2011,
  author = {Ji, Guomin and Zhai, Yaxin and Fang, Changfeng and Xu, Yuqing and Cui, Bin and Liu, Desheng},
  title = {The electronic transport properties in C60 molecular devices with different contact distances},
  journal = {Physics Letters A},
  year = {2011},
  volume = {375},
  number = {14},
  pages = {1602--1607},
  url = {http://www.sciencedirect.com/science/article/B6TVM-52966TY-3/2/5105656ff4b2940ba08ee728c19b2659},
  doi = {http://dx.doi.org/10.1016/j.physleta.2011.02.058}
}
    Kai-Tak Lam, Yunhao Lu, Yuan Ping Feng & Gengchiau Liang Stability and electronic structure of two dimensional C[sub x](BN)[sub y] compound

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 98(2), 022101-3     		 DOI URL 
    Abstract: The thermal stability and electronic structures of two dimensional Cx(BN)y compounds are studied using first-principles calculations based on the density functional theory. Although, from total energy calculations, it was well-established that phase-segregated atomic arrangements had the lowest energy, we found that due to the high activation energy required for phase-segregation process, evenly distributed configurations are stable at room temperature. Furthermore, the energy bandgap of the evenly distributed Cx(BN)y compounds is dependent on the carbon concentration. By controlling the carbon concentration in the compound, the EG of the compound
    material can be adjusted for electronic applications.
    Keywords: reaction path; ab initio calculations; carbon compounds; boron nitride; density functional theory; energy gap; segregation; thermal stability; total energy; ATK; Application
    Area: graphene
    BibTeX: 
    @article{Lam2011,
  author = {Lam, Kai-Tak and Lu, Yunhao and Feng, Yuan Ping and Liang, Gengchiau},
  title = {Stability and electronic structure of two dimensional C[sub x](BN)[sub y] compound},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {98},
  number = {2},
  pages = {022101--3},
  url = {http://link.aip.org/link/?APL/98/022101/1},
  doi = {http://dx.doi.org/10.1063/1.3535604}
}
    Enling Li, Xiqiang Wang, Liping Hou, Danna Zhao, Yuanbin Dai & Xuewen Wang Study on the Electronic Transport Properties of Zigzag GaN Nanotubes

    [Abstract] [BibTeX]

    		 2011 Journal of Physics: Conference Series
    Vol. 276(1), 012046     		 DOI URL 
    Abstract: The electronic transport properties of zigzag GaN nanotubes (n, 0) (4<=n<=9) have been calculated using the density functional theory and non-equilibrium Green's functions method. Firstly, the density functional theory (DFT) is used to optimize and calculate the electronic structure of GaNNTs (n, 0) (4<=n<=9). Secondly, DFT and non-equilibrium Green function (NEGF) method are also used to predict the electronic transport properties of GaNNTs two-probe system. The results showed: there is a corresponding relation between the electronic transport properties and the valley of state density of each GaNNT. In addition, the volt-ampere curve of GaNNT is approximately linear.
    Keywords: ATK; Application; GaN; nanotubes;
    Area: nanotubes
    BibTeX: 
    @article{Li2011,
  author = {Li, Enling and Wang, Xiqiang and Hou, Liping and Zhao, Danna and Dai, Yuanbin and Wang, Xuewen},
  title = {Study on the Electronic Transport Properties of Zigzag GaN Nanotubes},
  journal = {Journal of Physics: Conference Series},
  year = {2011},
  volume = {276},
  number = {1},
  pages = {012046},
  url = {http://stacks.iop.org/1742-6596/276/i=1/a=012046},
  doi = {http://dx.doi.org/10.1088/1742-6596/276/1/012046}
}
    Ling-Na Chen, Song-Shan Ma, Fang-Ping OuYang, Jin Xiao & Hui Xu First-principles study of metallic carbon nanotubes with boron/nitrogen co-doping

    [Abstract] [BibTeX]

    		 2011 Chinese Physics B
    Vol. 20(1), 017103     		 DOI URL 
    Abstract: Using the first-principles calculations, we investigate the electronic band structure and the quantum transport properties of metallic carbon nanotubes (MCNTs) with B/N pair co-doping. The results about formation energy show that the B/N pair co-doping configuration is a most stable structure. We find that the electronic structure and the transport properties are very sensitive to the doping concentration of the B/N pairs in MCNTs, where the energy gaps increase with doping concentration increasing both along the tube axis and around the tube, because the mirror symmetry of MCNT is broken by doping B/N pairs. In addition, we discuss conductance dips of the transmission spectrum of doped MCNTs. These unconventional doping effects could be used to design novel nanoelectronic devices.
    Keywords: ATK; Application; nanotube; doping
    Area: nanotubes
    BibTeX: 
    @article{LingNa2011,
  author = {Chen, Ling-Na and Ma, Song-Shan and OuYang, Fang-Ping and Xiao, Jin and Xu, Hui},
  title = {First-principles study of metallic carbon nanotubes with boron/nitrogen co-doping},
  journal = {Chinese Physics B},
  year = {2011},
  volume = {20},
  number = {1},
  pages = {017103},
  url = {http://stacks.iop.org/1674-1056/20/i=1/a=017103},
  doi = {http://dx.doi.org/10.1088/1674-1056/20/1/017103}
}
    Minggang Zeng, Lei Shen, Miao Zhou, Chun Zhang & Yuanping Feng Graphene-based bipolar spin diode and spin transistor: Rectification and amplification of spin-polarized current

    [Abstract] [BibTeX]

    		 2011 Physical Review B
    Vol. 83(11), 115427     		 DOI  
    Abstract: Using nonequilibrium Green's function method combined with density functional theory we report bipolar spin diode behavior in zigzag graphene nanoribbons (ZGNRs). Nearly ±100% spin-polarized current can be generated and tuned by a source-drain voltage and/or magnetic configurations in these two-terminal bipolar spin diodes. This unique transport property is attributed to the intrinsic transmission selection rule of the wave function of spin subbands near the Fermi level in ZGNRs. Moreover, the bias voltage and magnetic configurations of the two-terminal ZGNR-based spin diodes provide a rich variety of ways to control the spin current, which can be used to design three-terminal spin transistors. These ZGNRs-based components make possible the manipulation of spin-polarized current such as rectification and amplification for carbon-based spintronics.
    Keywords: ATK; Application; graphene; spin; bipolar; diode; rectification
    Area: graphene; spin
    BibTeX: 
    @article{Zeng2011,
  author = {Zeng, Minggang and Shen, Lei and Zhou, Miao and Zhang, Chun and Feng, Yuanping},
  title = {Graphene-based bipolar spin diode and spin transistor: Rectification and amplification of spin-polarized current},
  journal = {Physical Review B},
  publisher = {American Physical Society},
  year = {2011},
  volume = {83},
  number = {11},
  pages = {115427},
  doi = {http://dx.doi.org/10.1103/PhysRevB.83.115427}
}
    Minggang Zeng, Lei Shen, Haibin Su, Chun Zhang & Yuanping Feng Graphene-based spin logic gates

    [Abstract] [BibTeX]

    		 2011 Applied Physics Letters
    Vol. 98(9), 092110-3     		 DOI URL 
    Abstract: Logic operation is the key of digital electronics and spintronics. Based on spin-dependent transport property of zigzag graphene nanoribbons studied using nonequilibrium Green's function method and density functional theory, we propose a complete set of all-carbon spin logic gates, in which the spin-polarized current can be manipulated by the source-drain voltage and magnetic configuration of the electrodes. These logic gates allow further designs of complex spin logic operations and pave the way for full implementation of spintronics computing devices.
    Keywords: density functional theory; electrodes; graphene; Green's function methods; logic gates; magnetoelectronics; nanostructured materials; spin polarised transport; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{Zeng2011a,
  author = {Zeng, Minggang and Shen, Lei and and Su, Haibin and Zhang, Chun and Feng, Yuanping},
  title = {Graphene-based spin logic gates},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2011},
  volume = {98},
  number = {9},
  pages = {092110--3},
  url = {http://link.aip.org/link/?APL/98/092110/1},
  doi = {http://dx.doi.org/10.1063/1.3562320}
}
    Aiko Fukazawa, Manabu Kiguchi, Satoshi Tange, Yasunori Ichihashi, Qiang Zhao, Takuya Takahashi, Tatsuya Konishi, Kei Murakoshi, Yuta Tsuji, Aleksandar Staykov, Kazunari Yoshizawa & Shigehiro Yamaguchi Phosphine Sulfides as an Anchor Unit for Single Molecule Junctions

    [Abstract] [BibTeX]

    		 2011 Chemistry Letters
    Vol. 40(2), 174-176     		 DOI  
    Abstract: Phenylene and biphenyl compounds with dibenzophosphole sulfide (DBPS) as an anchoring group for single molecule junctions were synthesized. The conductance measurements revealed that the phosphine sulfide indeed acts as an anchoring group for Au electrodes. Theoretical calculations including metal electrodes demonstrated that the LUMO level of the DBPS-terminated biphenyl is close to the Au Fermi level, leading to the electron conduction of the Au-molecule-Au junction based on the resonance-tunneling mechanism.
    Keywords: molecular electronics; ATK; Application; single molecule junction;
    Area: molecular electronics
    BibTeX: 
    @article{Fukazawa2011,
  author = {Fukazawa, Aiko and Kiguchi, Manabu and Tange, Satoshi and Ichihashi, Yasunori and Zhao, Qiang and Takahashi, Takuya and Konishi, Tatsuya and Murakoshi, Kei and Tsuji, Yuta and Staykov, Aleksandar and Yoshizawa, Kazunari and Yamaguchi, Shigehiro},
  title = {Phosphine Sulfides as an Anchor Unit for Single Molecule Junctions},
  journal = {Chemistry Letters},
  year = {2011},
  volume = {40},
  number = {2},
  pages = {174--176},
  doi = {http://dx.doi.org/10.1246/cl.2011.174}
}
    Qin Han, Bing Cao, Liping Zhou, Guiju Zhang & Zhenghui Liu Electrical Transport Study of Single-Walled ZnO Nanotubes: A First-Principles Study of the Length Dependence

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(8), 3447-3452     		 DOI  
    Abstract: The electronic transport properties are characterized for single-walled zigzag (9, 0) ZnO nanotubes sandwiched between two lithium electrodes using a combined nonequilibrium Green's function and DFT-based formalism. By applying different bias voltages, the current-voltage characteristics are calculated for nanotubes of different lengths. The results indicate that the conductance of the system decreases exponentially with the increased length of the nanotubes. Metallic behavior is predicted for very short nanotubes, which is caused by the interface states from the metal-nanotubes interface. For longer nanotubes, the effect of the interface becomes smaller with the increased lengths. And semiconductor-like behaviors are observed, which are mainly determined by the ZnO nanotubes themselves. In addition, a peculiar phenomenon is observed that the values of the current at high bias are insensitive to the lengths. The behaviors can be understood in terms of the transmission spectrum, which shows that the transport properties are dominated by the electron states above the Fermi energy.
    Keywords: ZnO; nanotubes; ATK; Application;
    Area: nanotubes
    BibTeX: 
    @article{Han2011,
  author = {Han, Qin and Cao, Bing and Zhou, Liping and Zhang, Guiju and Liu, Zhenghui},
  title = {Electrical Transport Study of Single-Walled ZnO Nanotubes: A First-Principles Study of the Length Dependence},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {115},
  number = {8},
  pages = {3447--3452},
  doi = {http://dx.doi.org/10.1021/jp1089917}
}
    Aleksandar Staykov, Yuta Tsuji & Kazunari Yoshizawa Conductance through Short DNA Molecules

    [Abstract] [BibTeX]

    		 2011 The Journal of Physical Chemistry C
    Vol. 115(8), 3481-3490     		 DOI  
    Abstract: The conductance through short DNA molecules connected to gold electrodes is studied with density functional theory and nonequilibrium Green's function method combined with density functional theory. The anchoring of the molecules to the electrodes is investigated, and in addition to the covalent S-Au bond, weak interactions between the aromatic heterocyclic bases and the electrodes are found. These weak interactions are important for the electron transport through DNA molecules. A tunneling mechanism is suggested, and the conductive properties of the nucleotides in a metal-molecule-metal junction are compared. Different four-nucleotide DNA sequences are investigated. A significant value for the current, 20 pA, is calculated for 1.5 V applied bias for a DNA sequence consisting of guanine and cytosine nucleotides. It is shown that adenine-thymine nucleotide pairs introduce potential barriers for the electron transport and therefore significantly decline the conductance. The obtained results are compared with recent experimental observations (Nanotechnology2009, 20, 115502) and confirm the possibility for electron transport through DNA molecules as well as provide an explanation for the reduced conductance through DNA sequences, which contain adenine-thymine nucleotide pairs. The results are compared with a previous theoretical study, performed with the extended Hückel method (ChemPhysChem2003, 4, 1256), which reports low conductance for DNA molecules. The difference in the conclusions is due to the applied bias self-consistent field calculations used in the recent study, which take into account the changes of the transmission probabilities with the bias.
    Keywords: ATK; Application; molecular electronics; DNA;
    Area: molecular electronics
    BibTeX: 
    @article{Staykov2011,
  author = {Staykov, Aleksandar and Tsuji, Yuta and Yoshizawa, Kazunari},
  title = {Conductance through Short DNA Molecules},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {115},
  number = {8},
  pages = {3481--3490},
  doi = {http://dx.doi.org/10.1021/jp110803a}
}
    Cai-Juan Xia, De-Sheng Liu, Han-Chen Liu & Ying-Tang Zhang A possible salicylideneanilines-based optical molecular switch induced by a reversible hydrogen transfer: an ab initio study

    [Abstract] [BibTeX]

    		 2011 Molecular Physics: An International Journal at the Interface Between Chemistry and Physics
    Vol. 109(2), 209-215     		 DOI  
    Abstract: The electronic transport properties of the salicylideneanilines-based molecular optical switch are investigated using a nonequilibrium Green's function formalism combined with first-principles density functional theory. The molecule that comprises the switch can convert between the enol and keto tautomeric forms upon photoinduced excited state hydrogen transfer in the molecular bridge. Theoretical results show that the current through the enol form is significantly larger than that through the keto form, which realize the on and off states of the molecular switch. The physical origin of the switching behaviour is interpreted based on the spatial distributions of molecular orbitals and the HOMO-LUMO gap. Furthermore the effect of the donor/acceptor substituent on the electronic transport through the molecular device is also discussed in detail. The switching performance can be improved to some extent through the acceptor substituent.
    Keywords: ATK; Application; molecular switch; nonequilibrium Green's function; electronic transport; density functional theory; molecular electronics
    Area: molecular electronics
    BibTeX: 
    @article{Xia2011,
  author = {Xia, Cai-Juan and Liu, De-Sheng and Liu, Han-Chen and Zhang, Ying-Tang},
  title = {A possible salicylideneanilines-based optical molecular switch induced by a reversible hydrogen transfer: an ab initio study},
  journal = {Molecular Physics: An International Journal at the Interface Between Chemistry and Physics},
  publisher = {Taylor & Francis},
  year = {2011},
  volume = {109},
  number = {2},
  pages = {209--215},
  doi = {http://dx.doi.org/10.1080/00268976.2010.515255}
}
    Bidisa Das & Molly De Raychaudhury Electronic structure and transport properties of early transition metal tripledeckers

    [Abstract] [BibTeX]

    		 2011 Journal of Chemical Physics
    Vol. 134(1), 014709-10     		 DOI URL 
    Abstract: The electronic structure and transport properties of the Cp2BzM2 (M = Sc, Ti, and V) tripledeckers are studied by spin polarized density functional theory and nonequilibrium Green's function method considering high-spin and low-spin states. Total energy calculations show that the sandwich structured Cp2BzSc2 exists in a singlet state with no local magnetic moment on the Sc atoms. Cp2BzTi2 in triplet state exists as a distorted tripledecker and is more stable than singlet and quintet states. Cp2BzV2 stabilizes in the quintet state with a spin density of 2.4 on each vanadium atom. Hund's coupling plays a vital role in stabilizing the higher multiplets in case of titanium and vanadium clusters. In bigger clusters like Cp3Bz2M4, Sc multidecker has one unpaired spin, Ti multidecker has five unpaired spins, and V multidecker has seven unpaired spins in total. Spin polarized electronic transport is found for all states of vanadium tripledecker and one state of the titanium tripledecker when connected to a gold two probe junction. Moderate to high-spin filter efficiencies are calculated for these states. Cp2BzSc2 shows spin-independent electronic transport for all electronic states when introduced in the gold two probe junction. Current versus voltage curves are reported for selected clusters in the two probe setup.
    Keywords: density functional theory; electronic structure; Green's function methods; organic compounds; scandium compounds; spin polarised transport; titanium compounds; vanadium compounds; ATK; Application; spintronics
    Area: molecular electronics; spin
    BibTeX: 
    @article{Das2011,
  author = {Das, Bidisa and De Raychaudhury, Molly},
  title = {Electronic structure and transport properties of early transition metal tripledeckers},
  journal = {Journal of Chemical Physics},
  publisher = {AIP},
  year = {2011},
  volume = {134},
  number = {1},
  pages = {014709--10},
  url = {http://link.aip.org/link/?JCP/134/014709/1},
  doi = {http://dx.doi.org/10.1063/1.3524535}
}
    Irina Petreska, Ljupco Pejov & Ljupco Kocarev Exploring the possibilities to control the molecular switching properties and dynamics: A field-switchable rotor-stator molecular system

    [Abstract] [BibTeX]

    		 2011 Journal of Chemical Physics
    Vol. 134(1), 014708-12     		 URL 
    Abstract: A bistable, dipolar stator-rotor molecular system-candidate for molecular electronics is investigated. We demonstrate that it is possible to control the intramolecular torsional states and dynamics in this system by applying an appropriate additional electric field (instead of biasing one), achieving fine tuning and modulation of the relevant properties. The electric field effects on the quantities responsible for torsional dynamics (potential energy surface, potential barrier height, quantum and classical transition probabilities, correlation time, HOMO-LUMO gap) are studied from first principles. Our results indicate that it is possible to artificially stabilize the metastable conformational state of the studied molecule. The importance of this is evident, as the current-voltage characteristics of the metastable state are clearly distinguishable from the current-voltage characteristics of the two stable states. We report for the first time exact calculations related to the possibilities to control the thermally induced stochastic switching, and reduce the noise in a practical application. Thus, we believe that the molecule studied in this paper could operate as a field-switchable molecular device under real conditions.
    Keywords: ab initio calculations; electric field effects; librational states; metastable states; molecular electronics; potential energy surfaces; radiative lifetimes; rotors; stators; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Petreska2011,
  author = {Petreska, Irina and Pejov, Ljupco and Kocarev, Ljupco},
  title = {Exploring the possibilities to control the molecular switching properties and dynamics: A field-switchable rotor-stator molecular system},
  journal = {Journal of Chemical Physics},
  publisher = {AIP},
  year = {2011},
  volume = {134},
  number = {1},
  pages = {014708--12},
  url = {http://link.aip.org/link/?JCP/134/014708/1}
}
    Jing Yu, Guiling Zhang, Yan Shang, Hui Zhang, Luqing Yang, Tao Zeng, Bo Liu & Zesheng Li Rare earth element doping effect on the bonding and the transport property of delta-MoN

    [Abstract] [BibTeX]

    		 2011 Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)
    Vol. 128(3), 285-293     		 DOI  
    Abstract: Combining non-equilibrium Green's function technique with density functional theory, the rare earth element doping effect on the bonding and the transport property of delta-MoN were theoretically investigated. The Mo-N bond lengths become more uneven after dopings. Some Mo-N bonds were heavily lengthened by the La- and Gd-dopings, resulting in obvious damages of their bonding. Evident covalent-like La-N and Gd-N bonds were formed in La-MoN and Gd-MoN, respectively, while the Yb atom underwent an ionic-like interaction with its neighboring N atoms in Yb-MoN. A clear drop of the conductivity was found after La- and Gd-dopings. On the contrary, the conductivity was improved upon the Yb-doping. This case was rationalized from the carrier density and the scattering of the carriers. The backscattering effect was evident at the impurities. The La- and Gd-dopings could not effectively increase the carrier density near the Fermi level, while the Yb atom could offer f-carriers to transfer from the valence band to the conduction band.
    Keywords: ATK; Application; doping; interface; Rare earth element; Doping effect; d-MoN; Theoretical study
    Area: interfaces; semi
    BibTeX: 
    @article{Yu2011b,
  author = {Yu, Jing and Zhang, Guiling and Shang, Yan and Zhang, Hui and Yang, Luqing and Zeng, Tao and Liu, Bo and Li, Zesheng},
  title = {Rare earth element doping effect on the bonding and the transport property of delta-MoN},
  journal = {Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)},
  publisher = {Springer Berlin / Heidelberg},
  year = {2011},
  volume = {128},
  number = {3},
  pages = {285--293},
  doi = {http://dx.doi.org/10.1007/s00214-010-0845-0}
}
    Hongmei Liu, Nan Wang, Peng Li, Xing Yin, Cui Yu, Nengyue Gao & Jianwei Zhao Theoretical investigation into molecular diodes integrated in series using the non-equilibrium Green's function method

    [Abstract] [BibTeX]

    		 2011 Phys. Chem. Chem. Phys.
    Vol. 13(4), 1301-1306     		 DOI  
    Abstract: We have conducted a theoretical study on the electronic transport behaviour of two molecular diodes connected in series. The single diode is composed of o-nitrotoluene and o-aminotoluene connecting via a [sigma]-bridge, and the tandem diode is two single diodes connecting via a [small pi]-bridge. It was found that the rectification ratio was greatly improved due to the electronic coupling in the tandem diode. The rectification ratio of the tandem molecular diode can be 20 times higher than that of the single diode, which is quite different from a traditional diode. In addition, we also found that the high rectification ratio correlates with the intramolecular coupling of the tandem system. When long conjugated wires are employed in two single diodes, the rectification ratio is reduced.
    Keywords: ATK; Application; molecular electronics; diode; rectification;
    Area: molecular electronics
    BibTeX: 
    @article{Liu2011,
  author = {Liu, Hongmei and Wang, Nan and Li, Peng and Yin, Xing and Yu, Cui and Gao, Nengyue and Zhao, Jianwei},
  title = {Theoretical investigation into molecular diodes integrated in series using the non-equilibrium Green's function method},
  journal = {Phys. Chem. Chem. Phys.},
  publisher = {The Royal Society of Chemistry},
  year = {2011},
  volume = {13},
  number = {4},
  pages = {1301--1306},
  doi = {http://dx.doi.org/10.1039/C0CP00118J}
}
    Xia Cheng, Chuan-Lu Yang, Xiao-Fei Tong, Mei-Shan Wang & Xiao-Guang Ma Na effect on the electronic transport properties of C-20 H-20 molecule

    [Abstract] [BibTeX]

    		 2011 Acta Physica Sinica
    Vol. 60(1), 017302     		 URL 
    Abstract: Using first-principles density functional theory and non-equilibrium Green's function method, we investigate the electronic transport properties of Na@ C20H20 molecule. The calculational results show that the I-V curve exhibits good linear characteristic in the range of bias [-1, 1] V, and shows obvious negative differential resistance (NDR) characteristics. The equilibrium conductance of Na@ C20H20 molecule is 0. 0101 G(0). Comparing the results with those of Li @ C(20)H(20)molecule, we find that doping Na can improve both the electronic transport capacity and the chemistry stability of C20H20 molecule, which makes it more suitable as candidate of molecular device.
    Keywords: ATK; Application; fullerenes; negative differential resistance; NDR; doping
    Area: fullerenes
    BibTeX: 
    @article{Cheng2011,
  author = {Cheng, Xia and Yang, Chuan-Lu and Tong, Xiao-Fei and Wang, Mei-Shan and Ma, Xiao-Guang},
  title = {Na effect on the electronic transport properties of C-20 H-20 molecule},
  journal = {Acta Physica Sinica},
  year = {2011},
  volume = {60},
  number = {1},
  pages = {017302},
  url = {http://wulixb.iphy.ac.cn/cn/ch/common/view_abstract.aspx?flag=1&file_no=W20110191}
}
    R. Chowdhury, S. Adhikari, P. Rees, S.P. Wilks & F. Scarpa Graphene-based biosensor using transport properties

    [Abstract] [BibTeX]

    		 2011 Physical Review B
    Vol. 83(4), 045401     		 DOI  
    Abstract: The potential of graphene nanoribbons (GNR's) as molecular-scale sensors is investigated by calculating the electronic properties of the ribbon and the organic molecule ensemble. The organic molecule is assumed to be absorbed at the edge of a zigzag GNR. These nanostructures are described using a single-band tight-binding Hamiltonian. Their transport spectrum and density of states are calculated using the nonequilibrium Green's function formalism. The results show a significant suppression of the density of states (DOS), with a distinct response for the molecule. This may be promising for the prospect of GNR-based single-molecule sensors that might depend on the DOS (e.g., devices that respond to changes in either conductance or electroluminescence). Further, we have investigated the effect of doping on the transport properties of the system. The substitutional boron and nitrogen atoms are located at the center and edge of GNR's. These dopant elements have significant influence on the transport characteristics of the system, particularly doping at the GNR edge.
    Keywords: ATK; Application; graphene nanoribbon; sensor; adsorption;
    Area: graphene
    BibTeX: 
    @article{Chowdhury2011,
  author = {Chowdhury, R. and Adhikari, S. and Rees, P. and Wilks, S. P. and Scarpa, F.},
  title = {Graphene-based biosensor using transport properties},
  journal = {Physical Review B},
  publisher = {American Physical Society},
  year = {2011},
  volume = {83},
  number = {4},
  pages = {045401},
  doi = {http://dx.doi.org/10.1103/PhysRevB.83.045401}
}
    Shang-Chieh Hsieh, Shih-Min Wang & Feng-Yin Li A theoretical investigation of the effect of adsorbed NO2 molecules on electronic transport in semiconducting single-walled carbon nanotubes

    [Abstract] [BibTeX]

    		 2011 Carbon
    Vol. 49(3), 955-965     		 DOI  
    Abstract: We investigated the variation of electronic transport in a semiconducting single-walled carbon nanotube (SWCNT) due to NO2 molecules adsorbed on different locations of the SWCNT surface through a theoretical means. Our results indicate that the electronic conductance of a semiconducting SWCNT strongly depends on the distance between the electrode and the NO2 adsorption site. In some cases, the conductance variation can reach ten fold. Negative differential resistance behavior is identified in the current-voltage characteristics when a NO2 molecule is adsorbed on the surface of a semiconducting SWCNT. These phenomena originate from the interaction between the electrode and the NO2 due to the finite length of the SWCNT. A NO2 sensing mechanism of an SWCNT-based chemical sensor at low NO2 concentration was proposed. Several examples of this SWCNT-based sensor adsorbed with two NO2 molecules were used to demonstrate the complicated conductivity variation when the multiple NO2 adsorptions take place in an SWCNT-based NO2 gas sensor.
    Keywords: ATK; Application; nanotube; adsorption; sensor;
    Area: nanotubes
    BibTeX: 
    @article{Hsieh2011,
  author = {Hsieh, Shang-Chieh and Wang, Shih-Min and Li, Feng-Yin},
  title = {A theoretical investigation of the effect of adsorbed NO2 molecules on electronic transport in semiconducting single-walled carbon nanotubes},
  journal = {Carbon},
  year = {2011},
  volume = {49},
  number = {3},
  pages = {955--965},
  doi = {http://dx.doi.org/10.1016/j.carbon.2010.09.062}
}
    Sang Uck Lee, Hiroshi Mizuseki & Yoshiyuki Kawazoe Electron transport characteristics of one-dimensional heterojunctions with multi-nitrogen-doped capped carbon nanotubes

    [Abstract] [BibTeX]

    		 2010 Nanoscale
    Vol. 2(12), 2758-2764     		 DOI  
    Abstract: We present a systematic analysis of electron transport characteristics for one-dimensional heterojunctions with two multi-nitrogen-doped (multi-N-doped) capped carbon nanotubes (CNTs) facing one another at different numbers of nitrogen atoms and conformations. Our results show that the modification of the molecular orbitals by the nitrogen dopants generates conducting channels in the designed heterojunctions inducing multi-switching behavior with sequential negative differential resistance (NDR). The NDR behavior significantly depends on the doping site and conformation of doped nitrogen atoms. Furthermore, we provide a clear interpretation for the NDR behavior by a rigid shift model of the HOMO- and LUMO-filtered energy levels in the left and right electrodes under the applied biases. We believe that our results will give an insight into the design and implementation of various electronic logic functions based on CNTs for applications in the field of nanoelectronics.
    Keywords: ATK; Application; carbon nanotube; doping; NDR; negative differential resistance; switching;
    Area: nanotubes
    BibTeX: 
    @article{Lee2010,
  author = {Lee, Sang Uck and Mizuseki, Hiroshi and Kawazoe, Yoshiyuki},
  title = {Electron transport characteristics of one-dimensional heterojunctions with multi-nitrogen-doped capped carbon nanotubes},
  journal = {Nanoscale},
  publisher = {The Royal Society of Chemistry},
  year = {2010},
  volume = {2},
  number = {12},
  pages = {2758--2764},
  doi = {http://dx.doi.org/10.1039/C0NR00411A}
}
    R.N. Wang, X.H. Zheng, Z.X. Dai, H. Hao, L.L. Song & Z. Zeng Anchoring group effects in molecular devices: An ab initio study on the electronic transport of a carbon-dimer

    [Abstract] [BibTeX]

    		 2011 Physics Letters A
    Vol. 375(3), 657-660     		 DOI  
    Abstract: The conductance of a molecular device is sensitive to the contact geometry between the molecules and the probing electrodes. Taking a carbon-dimer C2 as an example and connecting it to the electrodes by different linking atoms H, Cu and S, we investigate the anchoring group effect in molecular devices by the first-principles approaches. The results exhibit that, depending on the anchoring groups and the subsequent different metal-molecule chemical bonds, the current varies over more than two orders of magnitude under the same bias. This emphasizes the great importance of the anchoring groups in molecular devices.
    Keywords: Anchoring group effects; Electronic transport; First-principles; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Wang2011a,
  author = {Wang, R.N. and Zheng, X.H. and Dai, Z.X. and Hao, H. and Song, L.L. and Zeng, Z.},
  title = {Anchoring group effects in molecular devices: An ab initio study on the electronic transport of a carbon-dimer},
  journal = {Physics Letters A},
  year = {2011},
  volume = {375},
  number = {3},
  pages = {657--660},
  doi = {http://dx.doi.org/10.1016/j.physleta.2010.11.031}
}
    Cui Yu, Hongmei Liu, Wenbin Ni, Nengyue Gao, Jianwei Zhao & Haoli Zhang Theoretical study of the source-drain current and gate leakage current to understand the graphene field-effect transistors

    [Abstract] [BibTeX]

    		 2011 Phys. Chem. Chem. Phys.
    Vol. 13(8), 3461-3467     		 DOI  
    Abstract: We designed acene molecules attached to two semi-infinite metallic electrodes to explore the source-drain current of graphene and the gate leakage current of the gate dielectric material in the field-effect transistors (FETs) device using the first-principles density functional theory combined with the non-equilibrium Green's function formalism. In the acene-based molecular junctions, we modify the connection position of the thiol group at one side, forming different electron transport routes. The electron transport routes besides the shortest one are defined as the cross channels. The simulation results indicate that electron transport through the cross channels is as efficient as that through the shortest one, since the conductance is weakly dependent on the distance. Thus, it is possible to connect the graphene with multiple leads, leading the graphene as a channel utilized in the graphene-based FETs in the mesoscopic system. When the conjugation of the cross channel is blocked, the junction conductance decreases dramatically. The differential conductance of the BA-1 is nearly 7 (54.57 [small mu ]S) times as large as that of the BA-4 (7.35 [small mu ]S) at zero bias. Therefore, the blocked graphene can be employed as the gate dielectric material in the top-gated graphene FET device, since the leakage current is small. The graphene-based field-effect transistors fabricated with a single layer of graphene as the channel and the blocked graphene as the gate dielectric material represent one way to overcome the problem of miniaturization which faces the new generation of transistors.
    Keywords: ATK; Application; graphene; field-effect transistor
    Area: graphene
    BibTeX: 
    @article{Yu2011,
  author = {Yu, Cui and Liu, Hongmei and Ni, Wenbin and Gao, Nengyue and Zhao, Jianwei and Zhang, Haoli},
  title = {Theoretical study of the source-drain current and gate leakage current to understand the graphene field-effect transistors},
  journal = {Phys. Chem. Chem. Phys.},
  publisher = {The Royal Society of Chemistry},
  year = {2011},
  volume = {13},
  number = {8},
  pages = {3461--3467},
  doi = {http://dx.doi.org/10.1039/C0CP01026J}
}
    P. Zhao, D.S. Liu, P.J. Wang, Z. Zhang, C.F. Fang & G.M. Ji First-principles study of the electronic transport properties of the anthraquinone-based molecular switch

    [Abstract] [BibTeX]

    		 2011 Physica B: Condensed Matter
    Vol. 406(4), 895-898     		 DOI  
    Abstract: By applying non-equilibrium Green's function (NEGF) formalism combined with first-principles density functional theory (DFT), we have investigated the electronic transport properties of the anthraquinone-based molecular switch. The molecule that comprises the switch can be converted between the hydroquinone (HQ) and anthraquinone (AQ) forms via redox reactions. The transmission spectra of these two forms are remarkably distinctive. Our results show that the current through the HQ form is significantly larger than that through the AQ form, which suggests that this system has attractive potential application in future molecular switch technology.
    Keywords: molecular switch; anthraquinone; non-equilibrium Green's function; electronic transport; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Zhao2011,
  author = {Zhao, P. and Liu, D.S. and Wang, P.J. and Zhang, Z. and Fang, C.F. and Ji, G.M.},
  title = {First-principles study of the electronic transport properties of the anthraquinone-based molecular switch},
  journal = {Physica B: Condensed Matter},
  year = {2011},
  volume = {406},
  number = {4},
  pages = {895--898},
  doi = {http://dx.doi.org/10.1016/j.physb.2010.12.023}
}
    Nikolai Lebedev, Igor Griva, Gary S. Kedziora, Anders Blom & Joel M. Schnur The Effect of Water on Electron Transfer through Conductive Oligo(phenylene vinylene) Quinones

    [Abstract] [BibTeX]

    		 2010 The Journal of Physical Chemistry C
    Vol. 114(51), 22710-22717     		 DOI  
    Abstract: Electron transfer (ET) through oxidized (QOPV) and reduced-protonated (HQOPV) forms of oligo(phenylene vinylene) quinone placed between two gold electrodes in the absence and presence of external water molecules is calculated using density functional theory with a nonequilibrium Green's function method. The results show that the presence of hydrogen atoms as an internal component (in reduced-protonated form of the molecule) screens the stimulating effect of oxygen on QOPV conductivity and eliminates the efficiency of the molecule conductance at low bias voltages. The formation of a complex with water restores the HQOPV conductivity at low biases and opens several additional strong conductivity channels below the Fermi level, substantially improving the efficiency of ET between QOPV and the electrode, especially at longer distances between the molecule and the metal. This effect of water can be utilized in the construction of novel highly efficient electrochemically gated electronic devices. It also opens a possibility for the fine regulation of direction of ET in "soft" molecular electronic devices with flexible organization and in biological systems.
    Keywords: ATK; Application; molecular electronics; OPV; water; gate
    Area: molecular electronics
    BibTeX: 
    @article{Lebedev2010a,
  author = {Lebedev, Nikolai and Griva, Igor and Kedziora, Gary S. and Blom, Anders and Schnur, Joel M.},
  title = {The Effect of Water on Electron Transfer through Conductive Oligo(phenylene vinylene) Quinones},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2010},
  volume = {114},
  number = {51},
  pages = {22710--22717},
  doi = {http://dx.doi.org/10.1021/jp108868z}
}
    Jakob Kryger Sørensen, Jeppe Fock, Anders Holmen Pedersen, Asger B. Petersen, Karsten Jennum, Klaus Bechgaard, Kristine Kilså, Victor Geskin, Jérôme Cornil, Thomas Bjørnholm & Mogens Brøndsted Nielsen Fulleropyrrolidine End-Capped Molecular Wires for Molecular Electronics - Synthesis, Spectroscopic, Electrochemical, and Theoretical Characterization

    [Abstract] [BibTeX]

    		 2011 The Journal of Organic Chemistry
    Vol. 76(1), 245-263     		 DOI  
    Abstract: In continuation of previous studies showing promising metal-molecule contact properties a variety of C60 end-capped "molecular wires" for molecular electronics were prepared by variants of the Prato 1,3-dipolar cycloaddition reaction. Either benzene or fluorene was chosen as the central wire, and synthetic protocols for derivatives terminated with one or two fullero[c]pyrrolidine "electrode anchoring" groups were developed. An aryl-substituted aziridine could in some cases be employed directly as the azomethine ylide precursor for the Prato reaction without the need of having an electron-withdrawing ester group present. The effect of extending the pi-system of the central wire from 1,4-phenylenediamine to 2,7-fluorenediamine was investigated by absorption, fluorescence, and electrochemical methods. The central wire and the C60 end-groups were found not to electronically communicate in the ground state. However, the fluorescence of C60 was quenched by charge transfer from the wire to C60. Quantum chemical calculations predict and explain the collapse of coherent electronic transmission through one of the fulleropyrrolidine-terminated molecular wires.
    Keywords: ATK; Application; molecular electronics; fullerene; molecular wires; experimental comparison
    Area: fullerenes
    BibTeX: 
    @article{Sorensen2011,
  author = {Sørensen, Jakob Kryger and Fock, Jeppe and Pedersen, Anders Holmen and Petersen, Asger B. and Jennum, Karsten and Bechgaard, Klaus and Kilså, Kristine and Geskin, Victor and Cornil, Jérôme and Bjørnholm, Thomas and Nielsen, Mogens Brøndsted},
  title = {Fulleropyrrolidine End-Capped Molecular Wires for Molecular Electronics - Synthesis, Spectroscopic, Electrochemical, and Theoretical Characterization},
  journal = {The Journal of Organic Chemistry},
  publisher = {American Chemical Society},
  year = {2011},
  volume = {76},
  number = {1},
  pages = {245--263},
  doi = {http://dx.doi.org/10.1021/jo102066x}
}
    GuiLing Zhang, HongLiang Yuan, Hui Zhang, Yan Shang, Miao Sun, Bo Liu & ZeSheng Li Theoretical studies of the transport property of oligosilane

    [Abstract] [BibTeX]

    		 2010 SCIENCE CHINA Chemistry
    Vol. 53(12), 2571-2580     		 DOI  
    Abstract: The transport mechanisms of four sigma-conjugated systems were comparatively studied by combining ATK and Gaussian 03 calculations. It was found that the charge-doped oligosilane behaved in a different way from the boron doped and phosphorus doped oligosilanes in terms of the transmission property. The charge-doped oligosilane showed almost no conductivity owing to the damage of the electron transfer path by charge-doping. By contrast, the boron doped and phosphorus doped oligosilanes were demonstrated to be good semiconductors and NDR behavior was observed for them. This is a reasonable result after the analysis of the transmission spectra, MPSH states, energy gap, conjugation effect, and scattering effect.
    Keywords: Chemistry; ATK; Application; oligosilane; theoretical study; transport property; oligosilane; doping; NDR;
    Area: molecular electronics
    BibTeX: 
    @article{Zhang2010b,
  author = {Zhang, GuiLing and Yuan, HongLiang and Zhang, Hui and Shang, Yan and Sun, Miao and Liu, Bo and Li, ZeSheng},
  title = {Theoretical studies of the transport property of oligosilane},
  journal = {SCIENCE CHINA Chemistry},
  publisher = {Science China Press, co-published with Springer},
  year = {2010},
  volume = {53},
  number = {12},
  pages = {2571--2580},
  doi = {http://dx.doi.org/10.1007/s11426-010-4147-0}
}
    Kurt Stokbro First-Principles Modeling of Molecular Single-Electron Transistors

    [Abstract] [BibTeX]

    		 2010 The Journal of Physical Chemistry C
    Vol. 114(48), 20461-20465     		 DOI URL 
    Abstract: We present a first-principles method for calculating the charging energy of a molecular single-electron transistor operating in the coulumb blockade regime. The properties of the molecule are modeled using density-functional theory, the environment is described by a continuum model, and the interaction between the molecule and the environment is treated self-consistently through the Poisson equation. The model is used to calculate the charge stability diagrams of a benzene and C60 molecular single-electron transistor.
    Keywords: ATK; Application; Background; single-electron transistors; Coulomb blockade; first-principles; charge stability diagram;
    Area: molecular electronics
    BibTeX: 
    @article{Stokbro2010a,
  author = {Stokbro, Kurt},
  title = {First-Principles Modeling of Molecular Single-Electron Transistors},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2010},
  volume = {114},
  number = {48},
  pages = {20461--20465},
  url = {http://pubs.acs.org/doi/abs/10.1021/jp104811r},
  doi = {http://dx.doi.org/10.1021/jp104811r}
}
    Feng Gao, Jianmin Qu & Matthew Yao Effects of local structural defects on the electron transport in a carbon nanotube between Cu electrodes

    [Abstract] [BibTeX]

    		 2010 Applied Physics Letters
    Vol. 97(24), 242112-3     		 DOI URL 
    Abstract: Using the first-principles approach with the Landauer formalism, we studied the effects of monovacancy and Stone-Wales defects on the electrical conductance of carbon nanotube (CNT) itself and its junction with copper electrodes. We found that the Stone-Wales defect has almost negligible impact on the electrical performance of the CNT(5,5) and its junction with copper at the Fermi level, while the monovacancy can reduce the electrical conductance of the CNT(5,5) significantly and that of the Cu/CNT(5,5)/Cu junction by more than 30%.
    Keywords: ab initio calculations; carbon nanotubes; copper; density functional theory; electrical conductivity; electrodes; Fermi level; Green's function methods; metal-semiconductor-metal structures; vacancies (crystal); ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Gao2010a,
  author = {Gao, Feng and Qu, Jianmin and Yao, Matthew},
  title = {Effects of local structural defects on the electron transport in a carbon nanotube between Cu electrodes},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2010},
  volume = {97},
  number = {24},
  pages = {242112--3},
  url = {http://link.aip.org/link/?APL/97/242112/1},
  doi = {http://dx.doi.org/10.1063/1.3527918}
}
    Yi-Peng An, Chuan-Lu Yang, Mei-Shan Wang, Xiao-Guang Ma & De-Hua Wang Ab initio investigations of the charge transport properties of endohedral M@C20 (M = Na and K) metallofullerenes

    [Abstract] [BibTeX]

    		 2010 Chinese Physics B
    Vol. 19(11), 113402     		 DOI URL 
    Abstract: Using density functional theory and quantum transport calculations based on nonequilibum Green's function formalism, we investigate the charge transport properties of endohedral M@C20 (M = Na and K) metallofullerenes. Our results show that the conductance of C 20 fullerene can be obviously improved by insertion of alkali atom at its centre. Both linear and nonlinear sections are found on the I-V curves of the Au-M@C20 -Au two-probe systems. The novel negative differential resistance behaviour is also observed in Na@C20 molecule but not in K@C20 .
    Keywords: negative differential resistance; conductance; first-principles; molecules; cluster; metal; metallofullerenes; electronic transport; density functional theory; nonequilibum Green's function; ATK; Application
    Area: fullerenes
    BibTeX: 
    @article{An2010b,
  author = {Yi-Peng An and Chuan-Lu Yang and Mei-Shan Wang and Xiao-Guang Ma and De-Hua Wang},
  title = {Ab initio investigations of the charge transport properties of endohedral M@C20 (M = Na and K) metallofullerenes},
  journal = {Chinese Physics B},
  year = {2010},
  volume = {19},
  number = {11},
  pages = {113402},
  url = {http://stacks.iop.org/1674-1056/19/i=11/a=113402},
  doi = {http://dx.doi.org/10.1088/1674-1056/19/11/113402}
}
    Y.D. Guo, X.H. Yan & Y. Xiao Spin-polarized current generated by carbon chain and finite nanotube

    [Abstract] [BibTeX]

    		 2010 Journal of Applied Physics
    Vol. 108(10), 104309-7     		 DOI URL 
    Abstract: Inspired by recent progress of experimental fabrication of carbon structure [ Borrnert et al., Phys. Rev. B 81, 085439 (2010) ], we proposed a scheme to generate spin-polarized current based on an all-carbon system consisting of carbon nanotube and chain. The transmission spectra are calculated based on density functional theory combined with nonequilibrium Green's function method. It is found that the spin-polarized current can be achieved in the proposed system by partial contact between nanotube and chain, without using the dopants, ferromagnetic electrodes, and external electric field. Moreover, our results show that the device containing carbon nanotubes with large length and diameter can produce the current with 100% spin polarization, which is essential for spintronic devices. Physical mechanisms and the comparison with the results of graphene are also discussed.
    Keywords: carbon nanotubes; density functional theory; Green's function methods; spin polarised transport; ATK; Application
    Area: nanotubes; spin
    BibTeX: 
    @article{Guo2010,
  author = {Guo, Y. D. and Yan, X. H. and Xiao, Y.},
  title = {Spin-polarized current generated by carbon chain and finite nanotube},
  journal = {Journal of Applied Physics},
  publisher = {AIP},
  year = {2010},
  volume = {108},
  number = {10},
  pages = {104309--7},
  url = {http://link.aip.org/link/?JAP/108/104309/1},
  doi = {http://dx.doi.org/10.1063/1.3510537}
}
    Zhiyong Wang, Keke Zhao, Hong Li, Zheng Liu, Zujin Shi, Jing Lu, Kazu Suenaga, Soon-Kil Joung, Toshiya Okazaki, Zhaoxia Jin, Zhennan Gu, Zhengxiang Gao & Sumio Iijima Ultra-narrow WS2 nanoribbons encapsulated in carbon nanotubes

    [Abstract] [BibTeX]

    		 2011 Journal of Materials Chemistry
    Vol. 21(1), 171-180     		 DOI  
    Abstract: Layered tungsten disulfide nanostructures are of both fundamental and technological interest. The widths of currently synthesized WS2 ribbons are in the microscale. By using single-walled carbon nanotubes and double-walled carbon nanotubes as templates, we fabricate WS2 nanoribbons with smooth zigzag edges and uniform widths down to 1-3 nm and layer numbers down to 1-3, dependent on the nanotube diameter. Although bulk WS2 is a nonmagnetic semiconductor, the ultra-narrow free-standing zigzag-edged WS2 nanoribbons turn out to be magnetic or nonmagnetic metals depending on the edge passivation way according to our first-principles calculations, whereas the ultra-narrow armchair-edged WS2 nanoribbons remain nonmagnetic semiconductors with a narrow gap.
    Keywords: ATK; Application; nanotube; tungsten disulfide; nanoribbon; magnetic materials;
    Area: nanotubes
    BibTeX: 
    @article{Wang2011,
  author = {Wang, Zhiyong and Zhao, Keke and Li, Hong and Liu, Zheng and Shi, Zujin and Lu, Jing and Suenaga, Kazu and Joung, Soon-Kil and Okazaki, Toshiya and Jin, Zhaoxia and Gu, Zhennan and Gao, Zhengxiang and Iijima, Sumio},
  title = {Ultra-narrow WS2 nanoribbons encapsulated in carbon nanotubes},
  journal = {Journal of Materials Chemistry},
  publisher = {The Royal Society of Chemistry},
  year = {2011},
  volume = {21},
  number = {1},
  pages = {171--180},
  doi = {http://dx.doi.org/10.1039/C0JM02821E}
}
    L. Zhu, K.L. Yao & Z.L. Liu Magnetic and electronic switching properties of photochromic diarylethene with two nitronyl nitroxides

    [Abstract] [BibTeX]

    		 2010 Applied Physics Letters
    Vol. 97(20), 202101-3     		 DOI URL 
    Abstract: Magnetic and electronic switching properties of single photochromic diarylethene with two nitronyl nitroxides sandwiched between two gold surfaces for closed and open configurations were investigated theoretically. Apart from the negative magnetoresistance effect in closed configuration, the negative differential resistance behavior in parallel state is also attained, which are potential for electronic applications. In addition, when using Br and H to substitute F atoms in the peripheral of cyclopentene, the on-off ratios are much smaller than that of the F-ligand one.
    Keywords: magnetic switching; magnetoresistance; molecular magnetism; negative resistance; organic compounds; photochromism; spin polarised transport; ATK; Application
    Area: molecular electronics; spin
    BibTeX: 
    @article{Zhu2010a,
  author = {Zhu, L. and Yao, K. L. and Liu, Z. L.},
  title = {Magnetic and electronic switching properties of photochromic diarylethene with two nitronyl nitroxides},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2010},
  volume = {97},
  number = {20},
  pages = {202101--3},
  url = {http://link.aip.org/link/?APL/97/202101/1},
  doi = {http://dx.doi.org/10.1063/1.3515420}
}
    Arijit Sen & Chao-Cheng Kaun Effect of Electrode Orientations on Charge Transport in Alkanedithiol Single-Molecule Junctions

    [Abstract] [BibTeX]

    		 2010 ACS Nano
    Vol. 4(11), 6404-6408     		 DOI  
    Abstract: Using first-principles calculations based on the density functional theory and the nonequilibrium Green's functions approach, we study the charge transport in Au-alkanedithiol-Au single-molecule junctions with different electrode orientations and molecular lengths. We attribute the recently measured high-/low-conductance in these heterostructures to two distinct electrode orientations, [100] and [111], which can control the electrode-molecule coupling as well as the tunneling strength by way of diverse band structures. Our detailed analysis on the transmission spectra suggests that even a single alkanedithiol junction can serve as a double quantum-dot system to yield tunable quantum interference.
    Keywords: ATK; Application; molecular electronics; gold nanowires; electronic transport; double quantum dot; tunable quantum interference; first-principles
    Area: molecular electronics
    BibTeX: 
    @article{Sen2010a,
  author = {Sen, Arijit and Kaun, Chao-Cheng},
  title = {Effect of Electrode Orientations on Charge Transport in Alkanedithiol Single-Molecule Junctions},
  journal = {ACS Nano},
  publisher = {American Chemical Society},
  year = {2010},
  volume = {4},
  number = {11},
  pages = {6404--6408},
  doi = {http://dx.doi.org/10.1021/nn101840a}
}
    Jun He, Ke-Qiu Chen, Zhi-Qiang Fan, Li-Ming Tang & W.P. Hu Transition from insulator to metal induced by hybridized connection of graphene and boron nitride nanoribbons

    [Abstract] [BibTeX]

    		 2010 Applied Physics Letters
    Vol. 97(19), 193305-3     		 DOI URL 
    Abstract: A hybridized structure constructed by zigzag boron nitride nanoribbon and zigzag graphene nanoribbon is proposed, and their band structures and electronic transport properties are calculated by applying first-principles calculations. The results show that the band gap of the hybridized structure can be tuned and transitions from insulator to metal can be realized by changing the unit number of zigzag graphene nanoribbon. The currents with different spin polarization display different behavior.
    Keywords: ab initio calculations; boron compounds; electron spin polarisation; energy gap; graphene; III-V semiconductors; metal-insulator transition; nanostructured materials; wide band gap semiconductors; ATK; Application
    Area: graphene; spin
    BibTeX: 
    @article{He2010,
  author = {He, Jun and Chen, Ke-Qiu and Fan, Zhi-Qiang and Tang, Li-Ming and Hu, W. P.},
  title = {Transition from insulator to metal induced by hybridized connection of graphene and boron nitride nanoribbons},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2010},
  volume = {97},
  number = {19},
  pages = {193305--3},
  url = {http://link.aip.org/link/?APL/97/193305/1},
  doi = {http://dx.doi.org/10.1063/1.3515921}
}
    L.H. Wang, Y. Guo, C.F. Tian, X.P. Song & B.J. Ding Torsion angle dependence of the rectifying performance in molecular device with asymmetrical anchoring groups

    [Abstract] [BibTeX]

    		 2010 Physics Letters A
    Vol. 374(48), 4876-4879     		 DOI URL 
    Abstract: Using first-principles density functional theory and nonequilibrium Green's function formalism, we investigate the effect of torsion angle on the rectifying characteristics of 4'-thiolate-biphenyl-4-dithiocarboxylate sandwiched between two Au(111) electrodes. The results show that the torsion angle has an evident influence on rectifying performance of such devices. By increasing the dihedral angle between two phenyl rings, namely changing the magnitude of the intermolecular coupling effect, a different rectifying behavior can be observed in these systems. Our findings highlight that the rectifying characteristics are intimately related to dihedral angles and can provide fundamental guidelines for the design of functional molecular devices.
    Keywords: Density functional theory; Nonequilibrium Green's function; Asymmetrical anchoring group; Rectifying performance; ATK; Application; molecular electronics
    Area: molecular electronics
    BibTeX: 
    @article{Wang2010c,
  author = {Wang, L.H. and Guo, Y. and Tian, C.F. and Song, X.P. and Ding, B.J.},
  title = {Torsion angle dependence of the rectifying performance in molecular device with asymmetrical anchoring groups},
  journal = {Physics Letters A},
  year = {2010},
  volume = {374},
  number = {48},
  pages = {4876--4879},
  url = {http://www.sciencedirect.com/science/article/B6TVM-515SRB8-1/2/f1365675c598962f90eeab1074861815},
  doi = {http://dx.doi.org/10.1016/j.physleta.2010.09.068}
}
    Sabyasachi Sen & Swapan Chakrabarti Ferromagnetically Coupled Cobalt-Benzene-Cobalt: The Smallest Molecular Spin Filter with Unprecedented Spin Injection Coefficient

    [Abstract] [BibTeX]

    		 2010 Journal of the American Chemical Society
    Vol. 132(43), 15334-15339     		 DOI  
    Abstract: Here, we predict that the ferromagnetically coupled cobalt-benzene-cobalt system will act as the smallest molecular spin filter with unprecedented spin injection coefficient. To validate our in-silico observation, we have performed state-of-the-art nonequilibrium Green's function calculations and analyzed the density of states of cobalt at the relativistic and nonrelativistic level of theory. Remarkably, we found that unpaired 3d electrons of cobalt are not participating in the spin transport process like other transition metal containing multidecker complexes. Instead, an admixture of the outer-sphere 4s and 4p orbitals of cobalt along with the 2p orbital of carbon of the benzene moiety is contributing to the singly occupied highest molecular orbital in the majority spin channel that creates a path for coherent spin transport leading to the extremely high spin injection coefficient of the system. The absence of the 3d electrons of cobalt in the spin transport process has been carefully examined, and it was found that the nodal structure of the 3d orbital of cobalt is not at all suitable for bonding in the cobalt-benzene-cobalt system. The whole study indicates that the underlying mechanism of the spin filter action in cobalt-benzene-cobalt is completely distinctive from the other known materials.
    Keywords: ATK; Application; spin; magnetic materials; molecular spin filter;
    Area: spin
    BibTeX: 
    @article{Sen2010,
  author = {Sen, Sabyasachi and Chakrabarti, Swapan},
  title = {Ferromagnetically Coupled Cobalt-Benzene-Cobalt: The Smallest Molecular Spin Filter with Unprecedented Spin Injection Coefficient},
  journal = {Journal of the American Chemical Society},
  publisher = {American Chemical Society},
  year = {2010},
  volume = {132},
  number = {43},
  pages = {15334--15339},
  doi = {http://dx.doi.org/10.1021/ja106705m}
}
    Changfeng Fang, Peng Zhao, Bin Cui, Lili Wang, Desheng Liu & Shijie Xie Current rectification in single molecule C59N: Effect of molecular polarity induced dipole moment

    [Abstract] [BibTeX]

    		 2010 Physics Letters A
    Vol. 374(43), 4465-4470     		 DOI URL 
    Abstract: By applying non-equilibrium Green's function formalism combined with density functional theory, we have investigated the electronic transport properties of nitrogen doped fullerene absorbed on the self-assembled alkanethiol monolayer. The molecular dipole moment, which in microscopy leads to the molecule-electrode coupling changing asymmetrically is responsible for the observed molecular rectification.
    Keywords: Electronic transport; Rectification; Dipole moment; Non-equilibrium Green's function; fullerene; molecular electronics; ATK; Application
    Area: fullerenes
    BibTeX: 
    @article{Fang2010,
  author = {Fang, Changfeng and Zhao, Peng and Cui, Bin and Wang, Lili and Liu, Desheng and Xie, Shijie},
  title = {Current rectification in single molecule C59N: Effect of molecular polarity induced dipole moment},
  journal = {Physics Letters A},
  year = {2010},
  volume = {374},
  number = {43},
  pages = {4465--4470},
  url = {http://www.sciencedirect.com/science/article/B6TVM-50YF6FN-4/2/55eb8c3104f6ad7e7913f5dab1e87f89},
  doi = {http://dx.doi.org/10.1016/j.physleta.2010.09.004}
}
    H. Liu, X. Chen & Y. Bu Redox-induced configuration conversion for thioacetamide dimer can function as a molecular switch

    [Abstract] [BibTeX]

    		 2010 Journal of Computational Chemistry
    Vol. 31(14), 2533-2539     		 DOI  
    Abstract: Abstract 10.1002/jcc.21512.abs The electronic switching properties of thioacetamide dimer (TAD) were investigated using the nonequilibrium Green's function method combined with density functional theory for design of a novel molecular switch. The H-bonded TAD can be converted upon hole-trapping to a three-electron (3e)-bonded configuration with a S∴S linkage which could provide a more favorable channel for charge transfer than the before. The redox-induced configuration conversion between the H-bonded and the 3e-bonded TADs could govern the charge migration through the molecular junction with a considerable difference in conduction currents. The calculated I–V characteristic curves of two configurations exhibit a switching behavior with an On-Off ratio in a range of about 4.3–7.6 within the applied voltages. Clearly, this hypothetical scheme provides a potential way to explore the novel conformation-dependent molecular switch. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010
    Keywords: thioacetamide dimer; molecular switch; charge conduction; H-bond and three-electron bond; DFT calculations; ATK; Application
    Area: molecular electronics
    BibTeX: 
    @article{Liu2010d,
  author = {Liu, H. and Chen, X. and Bu, Y.},
  title = {Redox-induced configuration conversion for thioacetamide dimer can function as a molecular switch},
  journal = {Journal of Computational Chemistry},
  publisher = {Wiley Subscription Services, Inc., A Wiley Company},
  year = {2010},
  volume = {31},
  number = {14},
  pages = {2533--2539},
  doi = {http://dx.doi.org/10.1002/jcc.21512}
}
    Shuji Abe Modeling of molecular switches and sensors

    [BibTeX]

    		 2010 CICSJ Bulletin
    Vol. 27(5), 124     		 URL 
    Keywords: ATK; molecular electronics; sensor; Application
    Area: molecular electronics
    BibTeX: 
    @article{Abe2010,
  author = {Shuji Abe},
  title = {Modeling of molecular switches and sensors},
  journal = {CICSJ Bulletin},
  year = {2010},
  volume = {27},
  number = {5},
  pages = {124},
  url = {http://www.jstage.jst.go.jp/article/cicsj/27/5/27_124/_article/-char/ja}
}
    J. Karamdel, M. Damghanian, F. Anian, F. Razaghian, C.F. Dee & B. Yeop Majlis Dependence of Band Structure and Carrier Concentration of Metallic (13,13) and Semiconducting (13,0) Single Wall Carbon Nanotube on Temperature

    [Abstract] [BibTeX]

    		 2010 Sains Malaysiana
    Vol. 39(4), 615-620     		 URL 
    Abstract: The electronic band structure, density of states (DOS) and carrier concentration of a (13,13) metallic and a (13,0) semiconducting Single Wall Carbon Nanotube (SWCNT) have been estimated and simulated by using the Fermi-Dirac distribution function. The energy dispersion E(k) relation for metallic SWCNT near the minimum energy is linear and the Fermi level was independent of temperature (T). On the other hand for semiconducting SWCNT the E(k) relation is parabolic. The normalized Fermi-Energy (EF-EC) in the nondegenerate regime is a weak (logarithmic) function of carrier concentration and varies linearly with T. In the degenerate condition, the Fermi level was independent of T and was a strong function of carrier concentration.
    Keywords: nanotubes; ATK; Application
    Area: nanotubes
    BibTeX: 
    @article{Karamdel2010,
  author = {J. Karamdel and M. Damghanian and F. Anian and F. Razaghian and C.F. Dee and B. Yeop Majlis},
  title = {Dependence of Band Structure and Carrier Concentration of Metallic (13,13) and Semiconducting (13,0) Single Wall Carbon Nanotube on Temperature},
  journal = {Sains Malaysiana},
  year = {2010},
  volume = {39},
  number = {4},
  pages = {615-620},
  url = {http://pkukmweb.ukm.my/~jsm/english_journals/vol39num4_2010/vol39num4_2010pg615-620.html}
}
    Hong Li, Xin Yan, Guangfu Luo, Rui Qin, Qihang Liu, Lili Yu, Chengyong Xu, Jiaxin Zheng, Jing Zhou, Jing Lu, Zhengxiang Gao, Shigeru Nagase & Wai Ning Mei Functionalized Metallic Single-Walled Carbon Nanotubes as a High-Performance Single-Molecule Organic Field Effect Transistor: An ab Initio Study

    [Abstract] [BibTeX]

    		 2010 The Journal of Physical Chemistry C
    Vol. 114(37), 15816-15822     		 DOI  
    Abstract: We propose a novel single-molecule organic field effect transistor (FET) fabricated via covalent functionalization of an individual metallic single-walled carbon nanotube (SWCNT). The transfer characteristic of this FET is calculated by using ab initio quantum transport calculations. Because of the significantly reduced screening effect of the quasi-one-dimensional electrode and seamless connection between the electrode and scattering region, the optimized device shows an excellent overall performance over the experimental single-molecule organic field effect transistors. This renders functionalized metallic SWCNTs a promising candidate for a high-performance single-molecule organic field effect transistor.
    Keywords: ATK; Application; nanotube; FET; transistors;
    Area: nanotubes
    BibTeX: 
    @article{Li2010d,
  author = {Li, Hong and Yan, Xin and Luo, Guangfu and Qin, Rui and Liu, Qihang and Yu, Lili and Xu, Chengyong and Zheng, Jiaxin and Zhou, Jing and Lu, Jing and Gao, Zhengxiang and Nagase, Shigeru and Mei, Wai Ning},
  title = {Functionalized Metallic Single-Walled Carbon Nanotubes as a High-Performance Single-Molecule Organic Field Effect Transistor: An ab Initio Study},
  journal = {The Journal of Physical Chemistry C},
  publisher = {American Chemical Society},
  year = {2010},
  volume = {114},
  number = {37},
  pages = {15816--15822},
  doi = {http://dx.doi.org/10.1021/jp106535q}
}
    Y.W. Li, Z.L. Yin, J.H. Yao, X.S. Deng & C.L. Yang Effect of CO adsorption on the electron transport behavior of single Fe-porphyrin molecular wire

    [Abstract] [BibTeX]

    		 2010 Physica E: Low-dimensional Systems and Nanostructures
    Vol. 43(1), 382-386     		 DOI URL 
    Abstract: The effect of CO adsorption on the electron transport behavior of single Fe-porphyrin molecular wire with sulfur end groups bonded to two gold (1 1 1) electrodes is investigated using nonequilibrium Green's function formalism combined with first-principles density functional theory. The current-voltage characteristics of the single Fe-porphyrin molecular wires with and without CO adsorption are calculated. The results demonstrate that Fe-porphyrin molecular wire shows a negative differential resistance (NDR) at 2.0 V. The molecular current through Fe-porphyrin is significantly reduced after CO adsorption. Such a significant difference indicates the potential application of Fe-porphyrin as a molecular sensor and/or a molecular switch. The molecular projected self-consistent Hamiltonian (MPSH) states and transmission coefficients of the single Fe-porphyrin molecular wires with and without CO adsorption are analyzed. It is found that the changes of the MPSH states of the single Fe-porphyrin molecular wires with and without CO adsorption lead to the switching behavior. Furthermore, the transmission coefficients of the single Fe-porphyrin molecular wires with and without CO adsorption under various external voltages are also investigated. The results show that the transmissions through the highest occupied MPSH and the lowest unoccupied MPSH states of the single Fe-porphyrin molecular wire are suppressed significantly at this external voltage of 2.0 V, which causes the NDR.
    Keywords: ATK; Application: molecular wire; negative differential resistance; molecular sensor;
    Area: molecular electronics
    BibTeX: 
    @article{Li2010e,
  author = {Li, Y.W. and Yin, Z.L. and Yao, J.H. and Deng, X.S. and Yang, C.L.},
  title = {Effect of CO adsorption on the electron transport behavior of single Fe-porphyrin molecular wire},
  journal = {Physica E: Low-dimensional Systems and Nanostructures},
  year = {2010},
  volume = {43},
  number = {1},
  pages = {382-386},
  url = {http://www.sciencedirect.com/science/article/B6VMT-50VKMHD-1/2/424045b7fd660f8ded6615f3b87eb191},
  doi = {http://dx.doi.org/10.1016/j.physe.2010.08.018}
}
    Ling-Na Chen, Song-Shan Ma, Fang-Ping Ouyang, Xiao-Zan Wu, Jin Xiao & Hui Xu Negative differential resistance behaviour in N-doped crossed graphene nanoribbons

    [Abstract] [BibTeX]

    		 2010 Chinese Physics B
    Vol. 19(9), 097301     		 DOI URL 
    Abstract: By using first-principles calculations and nonequilibrium Green's function technique, we study elastic transport properties of crossed graphene nanoribbons. The results show that the electronic transport properties of molecular junctions can be modulated by doped atoms. Negative differential resistance (NDR) behaviour can be observed in a certain bias region, when crossed graphene nanoribbons are doped with nitrogen atoms at the shoulder, but it cannot be observed for pristine crossed graphene nanoribbons at low biases. A mechanism for the negative differential resistance behaviour is suggested.
    Keywords: ATK; Application; graphene; doping; nanoribbon
    Area: graphene
    BibTeX: 
    @article{Ling-Na2010,
  author = {Chen, Ling-Na and Ma, Song-Shan and Ouyang, Fang-Ping and Wu, Xiao-Zan and Xiao, Jin and Xu, Hui},
  title = {Negative differential resistance behaviour in N-doped crossed graphene nanoribbons},
  journal = {Chinese Physics B},
  year = {2010},
  volume = {19},
  number = {9},
  pages = {097301},
  url = {http://stacks.iop.org/1674-1056/19/i=9/a=097301},
  doi = {http://dx.doi.org/10.1088/1674-1056/19/9/097301}
}
    Ebrahim Nadimi, Philipp Plänitz, Rolf Öttking, Karsten Wieczorek & Christian Radehaus First Principle Calculation of the Leakage Current Through SiO_2 and SiO_xN_y Gate Dielectrics in MOSFETs

    [Abstract] [BibTeX]

    		 2010 IEEE Transactions on Electron Devices
    Vol. 57(3), 690-695     		 DOI  
    Abstract: A combination of density functional theory and nonequilibrium Green's function formalism has been applied to the atomic scale calculation of the leakage current through SiO2 and SiOxNy dielectrics of MOSFETs. Samples with different dielectric thicknesses and nitrogen concentrations have been taken into account in order to study the dependence of the leakage current on these two parameters. It has been shown that the incorporation of nitrogen atoms into SiO2 increases the density of gap states, which leads to barrier lowering for both electrons and holes. The calculated leakage currents through different SiO2 polymorphs (e.g., b-cristobalite, a-quartz, and b-quartz) show thickness dependences, which are in very good agreement with measured values for amorphous SiO2. The dependence of the leakage current on the concentration of nitrogen atom in oxynitride gate dielectrics has also been calculated and shown to be in good agreement with the values extracted from measured data.
    Keywords: interface; gate dielectrics; ATK; Application; MOSFET; density functional theory; dielectric materials; leakage currents; silicon compounds; SiO2; atomic scale calculation; barrier lowering; density functional theory; dielectric thicknesses; first principle calculation; gap states; nitrogen concentrations; nonequilibrium Green's function formalism; oxynitride gate dielectrics; polymorphs; Density functional theory (DFT)
    Area: interfaces; semi
    BibTeX: 
    @article{Nadimi2010,
  author = {Ebrahim Nadimi and Philipp Plänitz and Rolf Öttking and Karsten Wieczorek and Christian Radehaus},
  title = {First Principle Calculation of the Leakage Current Through SiO_2 and SiO_xN_y Gate Dielectrics in MOSFETs},
  journal = {IEEE Transactions on Electron Devices},
  year = {2010},
  volume = {57},
  number = {3},
  pages = {690-695},
  doi = {http://dx.doi.org/10.1109/TED.2009.2038646}
}
    E. Nadimi, P. Plänitz, R. Öttking, M. Schreiber & C. Radehaus Single and Multiple Oxygen Vacancies in Ultrathin SiO2 Gate Dielectric and Their Influence on the Leakage Current: An Ab Initio Investigation

    [Abstract] [BibTeX]

    		 2010 IEEE Electron Device Letters
    Vol. 31(8), 881-883     		 DOI  
    Abstract: A first-principles method has been applied to the investigation of oxygen vacancies in ultrathin SiO2 gate dielectric and their influence on the gate leakage current. From the energy point of view, the most favorable site for a single vacancy has been determined to be at the Si/SiO2 interface. The formation energies of two neutral vacancies show, in general, an attractive interaction between two defects. Our results also indicate a correlation between the leakage current and the position of vacancies. As the number of vacancies increases in the oxide layer, the leakage current rises almost exponentially. A chain of five vacancies results in an increase of the leakage current by more than three orders of magnitude, which could be considered as gate-dielectric breakdown.
    Keywords: ATK; Application; dielectric materials; leakage currents; silicon compounds; SiO2; ab initio investigation; gate leakage current; gate-dielectric breakdown; multiple oxygen vacancies; ultrathin gate dielectrics; Density functional theory (DFT); MOSFET; dielectric breakdown; leakage current; nonequilibrium Green's function (NEGF); oxygen vacancy; reliability
    Area: interfaces; semi
    BibTeX: 
    @article{Nadimi2010a,
  author = {E. Nadimi and P. Plänitz and R. Öttking and M. Schreiber and C. Radehaus},
  title = {Single and Multiple Oxygen Vacancies in Ultrathin SiO2 Gate Dielectric and Their Influence on the Leakage Current: An Ab Initio Investigation},
  journal = {IEEE Electron Device Letters},
  year = {2010},
  volume = {31},
  number = {8},
  pages = {881-883},
  doi = {http://dx.doi.org/10.1109/LED.2010.2051013}
}
    Yun Ren, Ke-Qiu Chen, Jun He, Li-Ming Tang, Anlian Pan, B.S. Zou & Yan Zhang Mechanically and electronically controlled molecular switch behavior in a compound molecular device

    [Abstract] [BibTeX]

    		 2010 Applied Physics Letters
    Vol. 97(10), 103506-3     		 DOI URL 
    Abstract: A compound molecular device constructed by carbon nanotube, organic molecule, and metal electrode is proposed, and their electronic transport properties are calculated by using nonequilibrium Green's functions method in combination with the density-functional theory. The results show that mechanically controlled molecular switch, and electrically induced molecular switch behavior based on negative differential resistance can be observed in such molecular devices. The mechanism for the switch behavior is suggested.
    Keywords: carbon nanotubes; density functional theory; Green's function methods; spin polarised transport; ATK; Application
    Area: nanotubes; spin
    BibTeX: 
    @article{Ren2010b,
  author = {Ren, Yun and Chen, Ke-Qiu and He, Jun and Tang, Li-Ming and Pan, Anlian and Zou, B. S. and Zhang, Yan},
  title = {Mechanically and electronically controlled molecular switch behavior in a compound molecular device},
  journal = {Applied Physics Letters},
  publisher = {AIP},
  year = {2010},
  volume = {97},
  number = {10},
  pages = {103506--3},
  url = {http://link.aip.org/link/?APL/97/103506/1},
  doi = {http://dx.doi.org/10.1063/1.3488822}
}
    Anurag Srivastava, Neha Tyagi, U.S. Sharma & R.K. Singh Pressure induced phase transformation and electronic properties of AlAs

    [Abstract] [BibTeX]

    		 2011 Materials Chemistry and Physics
    Vol. 125(1-2), 66-71     		 DOI