Structural, vibrational and thermodynamics propertiesof Zn-based semiconductors

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 ΔF, the phonon contribution to the internal energy ΔE, the entropy S, and the constant-volume specific heat CV 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 − H298 have been also calculated and compared with the available experimental data.

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