Elastic constants and thermodynamic properties of AgY and CuY compounds under pressure and temperature effects

Abstract

Results of first principles calculations of the lattice parameter, elastic constants and some thermody-namic properties in a wide range of pressures and temperatures are reported for the B2 structure AgY and CuY. The calculated lattice and elastic constants at 0 K and 0 GPa are in agreement with the previous experimental and theoretical values. Using the density functional perturbation theory (DFPT) under the quasi-harmonic approximation (QHA), the evolution of some thermodynamic parameters concluding bulk modulus, volume expansion, thermal expansion coeff icient and heat capacity at constant pressure with temperature and pressure is computed. This is the first quantitative theoretical prediction of the reported properties and it still awaits experimental confirmation.