Regensburg 2016 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 41: Methods in Computational Materials Modelling I: Ab initio thermodynamics
MM 41.7: Vortrag
Mittwoch, 9. März 2016, 17:30–17:45, H52
Electron-phonon interactions in 2D materials: going beyond the limitations of plane-wave density-funtional theory — •Thibault Sohier1,2, Matteo Calandra2, and Francesco Mauri2,3 — 1THEOS and NCCR MARVEL, EPFL, Switzerland — 2IMPMC, Sorbonnes Universités, UPMC, UMR CNRS 7590, 4 place Jussieu, 75005 Paris, France — 3ISC-CNR and Dept of Physics, Sapienza University of Rome, P.le A. Moro 5, 00185, Rome, Italy
Electron-phonon interactions and their role in the transport properties of 2D materials are conceptual milestones for tomorrow's nanoelectronics. Electron-phonon interactions depend strongly on dimensionality, especially when long-range Coulomb interactions are involved, as in screened couplings or the coupling to polar optical phonons.
A key limitation of plane-wave density-functional perturbation theory with local functionals for the simulation of 2D materials is the use of periodic boundary conditions, implying the presence of periodic images of the 2D system in the out-of-plane direction. Long-range Coulomb interactions between those periodic images lead to incorrect electron-phonon couplings in 2D materials such as graphene or MoS2.
We develop novel approaches to eliminate the interactions between periodic images by truncating the Coulomb interaction in the out-of-plane direction. This is implemented for the calculation of total energy, forces, phonons and electron-phonon interactions, with possible addition of an asymmetric electric field to dope the 2D material. We use this method to investigate the peculiarity of the electron-phonon interaction in 2D materials like graphene and MoS2.