Lattice Dynamics of ZnTe: Phonon Dispersion, Multiphonon Infrared Spectrum, Mode Grüneisen Parameters, and Thermal Expansion

Abstract

A four-parameter rigid-ion model utilizing an effective ionic charge is used for the determination of phonon dispersion, phonon density of states, and the Debye characteristic temperature of ZnTe. Structures in the infrared spectrum of ZnTe are assigned to multiphonon combinations of various critical-point phonon frequencies. Using the long-wavelength optic-mode phonon frequencies as well as the elastic constants and their respective pressure derivatives as input data, the mode Gr\"uneisen parameters, the Gr\"uneisen constant, and the coefficient of thermal expansion of ZnTe are calculated.