Reference : The phonon dispersion of graphite revisited
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
http://hdl.handle.net/10993/17586
The phonon dispersion of graphite revisited
English
Wirtz, Ludger mailto [Department of Material Physics, University of the Basque Country, Centro Mixto CSIC-UPV, and Donostia International Physics Center (DIPC)]
Rubio, A. [Department of Material Physics, University of the Basque Country, Centro Mixto CSIC-UPV, and Donostia International Physics Center (DIPC)]
2004
Solid State Communications
Pergamon Press - An Imprint of Elsevier Science
131
3-4
141-152
Yes (verified by ORBilu)
International
0038-1098
[en] We review calculations and measurements of the phonon dispersion relation of graphite. First-principles calculations using density-functional theory are generally in good agreement with the experimental data since the long-range character of the dynamical matrix is properly taken into account. Calculations with a plane-wave basis demonstrate that for the in-plane optical modes, the generalized-gradient approximation (GGA) yields frequencies lower by 2% than the local-density approximation (LDA) and is thus in better agreement with experiment. The long-range character of the dynamical matrix limits the validity of force-constant approaches that take only interaction with few neighboring atoms into account. However, by fitting the force-constants to the ab initio dispersion relation, we show that the popular 4th-nearest-neighbor force-constant approach yields an excellent fit for the low frequency modes and a moderately good fit (with a maximum deviation of 6%) for the high-frequency modes. If, in addition, the non-diagonal force-constant for the second-nearest neighbor interaction is taken into account, all the qualitative features of the high-frequency dispersion can be reproduced and the maximum deviation reduces to 4%. We present the new parameters as a reliable basis for empirical model calculations of phonons in graphitic nanostructures, in particular carbon nanotubes. (C) 2004 Elsevier Ltd. All rights reserved.
http://hdl.handle.net/10993/17586
10.1016/j.ssc.2004.04.042

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