Phonon spectrum and thermal properties of semiconducting compounds ZnS and ZnSe

Phonon spectrum and thermal properties of semiconducting compounds ZnS and ZnSe have been calculated by using a proposed three-body shell model (TBSM).This model incorporates the effect of three-body and short-range repulsive forces, in addition to long-range Coulombic interactions in the frame work of rigid-shell model with both the ions polarizable. Using the above proposed model the phonon dispersion relations, phonon density of states and the Debye characteristic temperature have been calculated and plotted for the compounds ZnS and ZnSe. We find an overall good agreement between theoretical and experimental results.