Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 68: Electronic Structure Theory: Many-Body Effects

O 68.3: Poster

Mittwoch, 18. März 2015, 18:15–21:00, Poster A

Ab initio calculation of the first order Raman spectrum of graphene and graphite — •Albin Hertrich, Caterina Cocchi, Pasquale Pavone, and Claudia Draxl — Department of Physics, Humboldt-Universität zu Berlin, Germany

Raman scattering produced by fluctuations of the dielectric function caused by phonons is an important non-destructive method for characterizing carbon-based materials. By adopting a fully ab initio approach, we compute the first order Raman spectrum of graphene and graphite using the full-potential all-electron density-functional-theory (DFT) package exciting [1]. This code is based on the augmented plane-waves approach and allows for the calculation of both phonon-dispersion curves, within the frozen-phonon approximation, and frequency-dependent dielectric tensors, from time-dependent DFT and the Bethe-Salpeter equation. Starting from these ingredients, the first-order Raman scattering intensity (G peak) within the adiabatic approximation is obtained from the derivative of the dielectric function with respect to the normal coordinates of the optical phonons at the Γ point of the Brillouin zone and the vibrational matrix element. Our results are interpreted and discussed in comparison with the existing literature.

[1] A. Gulans et al. J. Phys.: Condens. Matter 26 (2014) 363202