First-principles calculations of the structural, phonon and thermal properties of ZnX (X = S, Se,Te) chalcogenides

Abstract

Zinc chalcogenides, ZnX (X = S, Se and Te), are investigated with the full-potential linear-augmented plane wave method within the framework of the density functional theory for their structural, phonon and thermal properties. We consider the generalized gradient approximation for the purpose of exchange-correlation energy determination. Murnaghan’s equation of state is used for volume optimization by minimizing the total energy with respect to the unit cell volume. The elastic constants are calculated to examine the crystal structure stability, binding properties and bond character of zinc chalcogenides. By means of frozen-phonon method within the harmonic approximation, we work out phonon dispersion, lattice dynamics and thermal properties of ZnX compounds. The phonon frequencies in the first Brillouin zone, at the zone centre (Γ) and at the zone boundary (X or L) are estimated. The calculated lattice parameters and thermal parameters are in good agreement with other theoretical calculations as well as with the available experimental data.