Density functional study of elastic, mechanical and thermodynamic properties of MgCu with a CsCl-type structure

We have employed the density functional theory plane-wave pseudo potential method, with local density approximation and generalized gradient approximation to perform first-principles quantum mechanics calculations in order to investigate the structural, elastic and mechanical properties of the intermetallic compound MgCu with a CsCl-type structure. The calculated equilibrium lattice constant is in good agreement with the experimental and theoretical values. The elastic constants were determined from a linear fit of the calculated stress-strain function according to Hooke's law. From the elastic constants, the bulk modulus B, anisotropy factor A, shear modulus G, Young's modulus E, Poisson's ratio υ, and the ratio B/G for MgCu compound are obtained. Our calculated results for the bulk modulus B, and Young's modulus E are consistent with the experimental and theoretical data. The sound velocities and Debye temperature are also predicted from elastic constants. Finally, the linear response method has been used to calculate the thermodynamic properties. The temperature dependence of the enthalpy H, free energy F, entropy S, and heat capacity at constant volume Cv of MgCu crystal in a quasi-harmonic approximation have been obtained from phonon density of states and discussed for the first report.