New ATK study on flexural-phonon scattering induced by electrostatic gating in graphene

Feb 03 2017

Two-dimensional materials are promising candidates for future electronic devices with properties that can be tuned by the electrostatic and dielectric environment. One of the applications is to use a gate to tune the electron-phonon coupling in order to control the carrier density precisely. Recently, researchers at the Technical University of Denmark published an article in Physical Review Letters 118, 046601 (2017) that describes a new flexural-phonon scattering mechanism induced by the electrostatic gating of a graphene device [1].

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Using the electron-phonon coupling and the mobility analysis tools [2] available in ATK, they studied the effect of gate-induced scattering on the mobility in several gated graphene device geometries and dielectrics.
The significant mobility degradation found was traced back to the broken planar mirror symmetry due to the gate-potential or dielectric environment that activates one-phonon scattering from flexural phonons. This reveals the importance of protecting the planar mirror symmetry to fully exploit the unique transport properties of graphene.
To check out our tutorial of how to calculate the phonon limited mobility in graphene, click here.

[1] T. Gunst, K. Kaasbjerg, M. Brandbyge, “Flexural phonon scattering induced by electrostatic gating in graphene”, Physical Review Letters 118, 046601 (2017).
[2] T. Gunst, T. Markussen, K. Stokbro, M. Brandbyge, “First-principles method for electron-phonon coupling and electron mobility: Applications to 2D materials”, Phys. Rev. B, 93, 035414 (2016).