Two-dimensional analysis of the double-resonant 2D Raman mode in bilayer graphene.
By computing the double-resonant Raman scattering cross section completely from first principles and including the electron-electron interaction at the GW level, we unravel the dominant contributions for the double-resonant 2D mode in bilayer graphene. We show that, in contrast to previous works, the so-called inner processes are dominant and that the 2D-mode line shape is described by three dominant resonances around the K point. We show that the splitting of the transversal optical (TO) phonon branch in the Γ-K direction, as large as 12  cm(-1) in the GW approximation, is of great importance for a thorough description of the 2D-mode line shape. Finally, we present a method to extract the TO phonon splitting and the splitting of the electronic bands from experimental data.
Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
Felix
F
Herziger
Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie, UMR CNRS 7590, Sorbonne Universités, UPMC Université Paris 06, MNHN, IRD, 4 Place Jussieu, F-75005 Paris, France.
Matteo
M
Calandra
Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie, UMR CNRS 7590, Sorbonne Universités, UPMC Université Paris 06, MNHN, IRD, 4 Place Jussieu, F-75005 Paris, France.
Paola
P
Gava
Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
Patrick
P
May
Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie, UMR CNRS 7590, Sorbonne Universités, UPMC Université Paris 06, MNHN, IRD, 4 Place Jussieu, F-75005 Paris, France.
Michele
M
Lazzeri
Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie, UMR CNRS 7590, Sorbonne Universités, UPMC Université Paris 06, MNHN, IRD, 4 Place Jussieu, F-75005 Paris, France.
Francesco
F
Mauri
Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
Janina
J
Maultzsch