Structural and elastic properties of Mg3CuH0.6 ternary hydride by ab initio study

In the present work, we investigate the structural and elastic properties of a new intermetallic hydride compound Mg3CuH0.6. The theoretical study has been carried out based on density functional theory (DFT), within local density approximation (LDA) and generalized gradient approximation (GGA). The calculated structural parameters of Mg3CuH0.6 compound are consistent with the available experimental data in both approximations. The heat of formation found shows that this compound has a stable structure. According to Hooke's law which leads to a linear relation between stress and strain, the elastic constants were determined. Once the elastic constants are obtained, the bulk modulus B, shear modulus G, Young's modulus E, Poisson's ratio σ, for Mg3CuH0.6 compound were deduced using Voigt-Reuss-Hill (VRH) approximation. The results show that this alloy exhibit ductile property. Finally, the Debye temperature is also calculated and discussed for the first time. This will be considered as the first quantitative theoretical prediction of these properties.