Phonon surface mapping of graphite: Disentangling quasi-degenerate phonon dispersions

Alexander Grüneis, J Serrano, A Bosak, M Lazzeri, S.L. Molodtsov, Ludger Wirtz, Claudio Attaccalite, M Krisch, Angel Rubio, F Mauri, Thomas Pichler

Publications: Contribution to journalArticlePeer Reviewed

Abstract

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/Å)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.
Original languageEnglish
Article number085423
Number of pages5
JournalPhysical Review B
Volume80
Issue number8
DOIs
Publication statusPublished - 2009

Austrian Fields of Science 2012

  • 103015 Condensed matter

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