First-Principles Investigations on Structural, Elastic, and Thermodynamic Properties of CaX (X = S, Se, and Te) under Pressure

We have investigated the structural, elastic and thermodynamic properties of CaX (X = S, Se, and Te) using first-principles calculations. The exchange-correlation functional employed is the generalized gradient approximation of Wu and Cohen (GGA-WC). The estimated structural properties of these compounds are in excellent agreement with experimental data. The stability of the compounds was discussed on basis of the calculated elastic constants C ij , which are in good agreement with the experimental results. The thermodynamic properties of CaX materials are also calculated. Furthermore, the effects of temperature and pressure upon the heat capacities, expansion coefficients and bulk modulus have been calculated and discussed.