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HL: Fachverband Halbleiterphysik
HL 12: Graphene: mostly Theory (with O/TT)
HL 12.2: Vortrag
Montag, 16. März 2015, 15:15–15:30, ER 164
Two-dimensional analysis of the double-resonant 2D Raman mode in bilayer graphene — •Felix Herziger1, Matteo Calandra2, Paola Gava2, Patrick May1, Michele Lazzeri2, Francesco Mauri2, and Janina Maultzsch1 — 1Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin, Germany — 2IMPMC, Université Pierre et Marie Curie, CNRS, 75252 Paris, France
The double-resonant 2D-mode Raman process in bilayer graphene has been discussed controversially in recent years. In this context, different models were proposed to explain the complex lineshape observed in experiments.
Using a two-dimensional first-principles calculation, we investigate the dominant contributions to the double-resonant Raman scattering cross-section of the 2D mode in bilayer graphene [1]. In contrast to previous works, we demonstrate that so-called ’inner’ processes are, by far, the most dominant processes, as in single-layer graphene. Moreover, we show that the splitting between the two TO-derived phonon branches in bilayer graphene cannot be neglected for a consistent understanding of the 2D-mode lineshape. Additionally, we investigate the contributions from both TO branches to the symmetric and anti-symmetric scattering processes. Our results answer the long-standing question regarding the different contributions to the 2D-mode lineshape in bilayer graphene.
[1] F. Herziger, M. Calandra, P. Gava, P. May, M. Lazzeri, F. Mauri, and J. Maultzsch, Phys. Rev. Lett. 113, 187401 (2014)