Lattice dynamics of GaSe

Abstract

Neutron inelastic scattering measurements of the phonon dispersion relation of GaSe have been analysed in terms of a simple axially symmetric Born-von K\'arm\'an force-constant model. The results show that the interlayer interaction is very weak compared with the intralayer ones. The model obtained from this analysis has provided the basis for a calculation of the frequency distribution function for GaSe and this in turn has been used to calculate the Debye temperature and the lattice specific heat as a function of temperature. The agreement with the measured heat capacity is excellent. The two-phonon spectra are also calculated.