Dispersion Curves and Elastic Constants of Graphite

Abstract

Lattice vibrations of the hexagonal graphite crystal are analyzed using two-body carbon-carbon interaction potentials. The potential parameters are obtained from estimates of the long-wavelength frequencies of graphite and a knowledge of the nitrogen-nitrogen potential parameters. The dispersion relations along high-symmetry directions are calculated showing excellent agreement with the experimental observations along ($00\xi$). The elastic constants of graphite are also calculated and compared with the available experimental data. There is general agreement between the theoretical calculations and the experimental observations.