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O: Fachverband Oberflächenphysik

O 93: Graphene II: Electronic Structure and Growth

O 93.2: Vortrag

Freitag, 31. März 2023, 10:45–11:00, GER 37

Raman features of graphene and weyl semimetals beyond the standard nonadiabatic theory — •Nina Girotto and Dino Novko — Institute of Physics, Zagreb, Croatia

Although graphene has already been thoroughly studied with Raman spectroscopy, there still exists a disagreement about the broadening mechanisms of the E2g mode and its actual temperature dependence [Nano Lett. 10, 466 (2010)]. Along with the importance of the nonadiabatic effects in graphene, higher order electron-phonon scattering processes also significantly impact the phonon spectrum. Specifically, the electron-phonon-induced lifetime and energy renormalization of the electron-hole pair excitations bring additional temperature dependence in the electron-coupled phonon modes and their corresponding linewidths. The nonadiabatic theory relying on first principles calculations, developed in [Phys. Rev. B 98, 041112(R) (2018)], is here successfully applied to graphene in various doping regimes and to Weyl semimetals, which contain a 3-dimensional analog of Dirac points in the electron band structure and are, therefore, excellent candidates for achieving a nonadiabatic regime.