Structural, vibrational and thermodynamics propertiesof Zn-based semiconductors

Abstract

We have preformed first-principle calculations for the structural, vibrational and thermodynamic properties of the IIB–VIA Zn-based semiconductor compounds ZnX (X = O, S, Se, Te). The phonon dispersion curves along several high-symmetry lines at the Brillouin zone together with the corresponding phonon density of states are calculated using density-functional perturbation theory. The calculated phonon frequencies at the Γ, X, and L points of the Brillouin zone show good agreement with the experimental values and other calculations. The thermodynamics properties including the phonon contribution to the Helmholtz free energy Δ F, the phonon contribution to the internal energy Δ E, the entropy S, and the constant-volume specific heat C V are determined within the harmonic approximation based on the calculated phonon dispersion relations. If 298 K is taken as a reference temperature, the difference values of H − H 298 have been also calculated and compared with the available experimental data.