Phonon dispersion curves in indium phosphide

Abstract

Phonon frequencies of indium phosphide have been determined along the principal symmetry directions (by inelastic neutron scattering). The shapes of the dispersion curves are discussed. The phonon frequencies at the critical points are: Gamma point, 10.3 and 9.2; X point, 9.95, 9.70, 5.8, 2.05; L point, 10.2, 9.5, 5.00, 1.65 THz. In all cases the longitudinal vibrations have a higher frequency than the transverse vibrations, i.e. the surfaces do not cross.