Ground State Stability and Thermal Properties of ErCu Using First Principles Study

Abstract

We have investigated elastic, vibrational and thermal properties of B2 type ErCu intermetallic compound using density functional theory (DFT). The positive phonon frequencies reflect the dynamical stability of ErCu intermetallic compound in the B2 type cubic structure phase. Furthermore, the density functional perturbation theory (DFPT) as implemented in quasi-harmonic approximation (QHA) was used for the calculation of thermal properties such as vibrational energy ΔF, entropy S, internal energy ΔE and constant-volume specific heat Cv of the ErCu. The entropy of ErCu is ~ 18 J∙K – 1∙mol – 1 that concluded that, the ErCu compound is not harder compound. The computed Poisson’s ratio (σ), Young’s modulus (E), bulk modulus (B) and shear modulus (GH) are 0.30, 66.65 GPa, 62.99 GPa and 25.18 GPa respectively. The B/GH ratio is 2.50, which confirmed the good ductility of ErCu intermetallic compound.