First-Principles Investigation of the Structural, Elastic and Thermodynamic Properties of CaRu2X2 (X = P, As) under Pressure

The structural, elastic and thermodynamic properties of CaRu2As2 and CaRu2P2 under pressure effect up to 18 GPa were determined through density functional theory calculations. The calculated equilibrium lattice parameters are in good agreement with the available experimental findings. The computed single-crystal elastic constants show that the title compounds are mechanically stable in all the considered pressure range (0–18 GPa). The title compounds exhibit a strong elastic anisotropy. Pressure-dependence of the single-crystal elastic constants and polycrystalline elastic moduli, namely bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio, was successfully determined. Debye temperature, average sound velocity, minimum thermal conductivity (Kmin), Vickers hardness (HV) and melting temperature (Tm) of the title compounds were calculated for a pressure range from 0 to 18 GPa.