Lattice Dynamics of Wurtzite: CdS. II

Abstract

A new model for the lattice dynamics of semi-ionic compounds is presented and applied to the computation of phonon dispersion in CdS. The calculated two-phonon density of states as a function of frequency is in agreement with measured infrared absorption in the two-phonon region. Improved values of the microscopic dielectric, elastic, and piezoelectric coefficients result from a self-consistent least-squares fit of model parameters. The model includes valence-band forces, rigid-ion Coulomb forces, and electronic and ionic polarization; it may be generally applicable to other semi-ionic II-VI compounds.