[en] The two-dimensional mapping of the phonon dispersions around the K point of graphite by inelastic x-ray scattering is provided. The present work resolves the longstanding issue related to the correct assignment of transverse and longitudinal phonon branches at K. We observe an almost degeneracy of the three TO-, LA-, and LO-derived phonon branches and a strong phonon trigonal warping. Correlation effects renormalize the Kohn anomaly of the TO mode, which exhibits a trigonal warping effect opposite to that of the electronic band structure. We determined the electron-phonon coupling constant to be 166 (eV/A degrees)(2) in excellent agreement to GW calculations. These results are fundamental for understanding angle-resolved photoemission, double-resonance Raman and transport measurements of graphene-based systems.
Disciplines :
Physics
Author, co-author :
Grueneis, A.; Faculty of Physics, University of Vienna / IFW–Dresden
Serrano, J.; CREA–Departamento de Fisica Aplicada, Universitat Politecnica de Catalunya
Bosak, A.; European Synchrotron Radiation Facility
Lazzeri, M.; IMPMC, IPGP, Universités Paris 6 et 7, CNRS
Molodtsov, S. L.; Institut für Festkörperphysik, TU Dresden
Wirtz, Ludger ; Institute for Electronics, Microelectronics, and Nanotechnology (CNRS UMR 8520), Dept. ISEN
Attaccalite, C.; Nano-Bio Spectroscopy Group and ETSF Scientific Development Centre, Dpto. Física de Materiales, Universidad del País Vasco, Centro de Física de Materiales CSIC-UPV/EHU-MPC and DIPC
Krisch, M.; European Synchrotron Radiation Facility
Rubio, A.; Nano-Bio Spectroscopy Group and ETSF Scientific Development Centre, Dpto. Física de Materiales, Universidad del País Vasco, Centro de Física de Materiales CSIC-UPV/EHU-MPC and DIPC / Fritz-Haber-Institute of the Max Planck Society, Theory Department
Mauri, F.; MPMC, IPGP, Universités Paris 6 et 7, CNRS
Pichler, T.; Faculty of Physics, University of Vienna
Language :
English
Title :
Phonon surface mapping of graphite: Disentangling quasi-degenerate phonon dispersions
