Structural, elastic and thermodynamic properties under pressure and temperature effects of MgIn _2S _4 and CdIn _2S _4

摘要

A density functional-based method is used to investigate the structural, elastic and thermodynamic properties of the cubic spinel semiconductors MgIn _2S _4 and CdIn _2S _4 at different pressures and temperatures. Computed ground structural parameters are in good agreement with the available experimental data. Single-crystal elastic parameters are calculated for pressure up to 10 GPa and temperature up to 1200 K. The obtained elastic constants values satisfy the requirement of mechanical stability, indicating that MgIn _2S _4 and CdIn _2S _4 compounds could be stable in the investigated pressure range. Isotropic elastic parameters for ideal polycrystalline MgIn _2S _4 and CdIn _2S _4 aggregates are computed in the framework of the Voigt-Reuss-Hill approximation. Pressure and thermal effects on some macroscopic properties such as lattice constant, volume expansion coefficient and heat capacities are predicted using the quasi-harmonic Debye model in which the lattice vibrations are taken into account.