colloquiums  |  Physics

Theo. Kolloquium: Coupling to flexural phonons in graphene with broken mirror reflection symmetry

Monday, 16. January 2017
13.30 – 15.00

P 603


Dr. Kristen Kaasbjerg, Technical University of Denmark

In graphene, the intrinsic electron-phonon coupling to the low-energy out-of-plane flexural phonons is quadratic in the phonon deflection of the graphene sheet due to the mirror reflection symmetry in the plane (z -> -z). However, in experimental situations where graphene is positioned in an electric gate field or supported by a substrate, the mirror reflection symmetry is often broken and a linear electron-phonon coupling to the highly excited flexural modes arises. In this talk, I will discuss the different mechanisms which can break the mirror reflection symmetry and present simple model as well as atomistic calculations of the resulting electron-phonon interaction. Finally, I will discuss the impact on 1) the low-field conductivity in graphene, and 2) the electron-limited Q-factor in graphene-based nanomechanical resonators.