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##### Questions and Answers / Re: restart of phonon calculation

« Last post by**Petr Khomyakov**on

*May 26, 2018, 17:24*»

This will be possible in the new version of QuantumATK-2018.06.

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This will be possible in the new version of QuantumATK-2018.06.

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Dear ATK users,

I am doing a phonon calculation but the job has stopped due to our system problem but some phonon steps have already been calculated (say up to displacement_10). Is there any way by which calculation will start from displacement_11???

I am doing a phonon calculation but the job has stopped due to our system problem but some phonon steps have already been calculated (say up to displacement_10). Is there any way by which calculation will start from displacement_11???

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Wow!!! I am impressed with this new feature of VNL. Thanks Petr.

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Thanks for the reply! That clarifies a lot!

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I did not say that you cannot study the electron transport through a ballistic conductor. It is totally up to you and your research project goals.

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You are comparing studies done for two different material systems: nanowire vs thin film.

Moreover, one study is done using semi-empirical tight-binding model, whereas the other one is based on ab-initio density functional theory.

In addition, the tight-binding study is likely using electron-phonon coupling constants obtained from bulk 3D calculations unlike the DFT study in which the electron-phonon coupling is computed for the actual low-dimensional system, taking into account surface phonons.

Also, the DFT-based calculations in the QuantumATK were done with two rather different methods (special thermal displacement and LOE) to account for electron-phonon interaction, and these two methods give similar results. So, I would question the reliability of the tight-binding-based calculations in the other paper.

You may consider carefully reading the two papers and try to understand what are the approximations used in these two rather different works for describing the electronic structure and the electron-phonon interaction of Si nanostructures.

Moreover, one study is done using semi-empirical tight-binding model, whereas the other one is based on ab-initio density functional theory.

In addition, the tight-binding study is likely using electron-phonon coupling constants obtained from bulk 3D calculations unlike the DFT study in which the electron-phonon coupling is computed for the actual low-dimensional system, taking into account surface phonons.

Also, the DFT-based calculations in the QuantumATK were done with two rather different methods (special thermal displacement and LOE) to account for electron-phonon interaction, and these two methods give similar results. So, I would question the reliability of the tight-binding-based calculations in the other paper.

You may consider carefully reading the two papers and try to understand what are the approximations used in these two rather different works for describing the electronic structure and the electron-phonon interaction of Si nanostructures.

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You have to calculate the band structure (BS) and the projected density of states (PDOS), using the BandStructure and ProjectedDensityOfStates analysis objects available through the GUI in the Scripter. When computed, you should open the BS and PDOS plots using the corresponding visualization plugins as usual.

In the lower right corner of both BS and PDOS plots there is an icon. Drag that icon from one window to the other, and you will be given the option to superimpose them, select BS/PDOS to get the combined plot.

In the lower right corner of both BS and PDOS plots there is an icon. Drag that icon from one window to the other, and you will be given the option to superimpose them, select BS/PDOS to get the combined plot.

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You need to get objects (for instance, BS, DOS, PLDOS) on the lab floor to plot, after your calculation is done, which should be included the analysis object. You can easily plot it.

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It is unfortunately not possible either.

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Thanks. And what about possibility to port existing VNL-GUI (academic) licences to a new system?