Structural, anisotropic elastic and electronic properties of Sr-Zn binary system intermetallic compounds : A first-principles study

We have studied the structural, anisotropic elastic and electronic properties of Sr-Zn binary intermetallic compounds using first-principles plane-wave pseudo-potential method. Our calculated equilibrium lattice parameters are validated by comparison with available experimental data. Results of formation enthalpy have indicated that each intermediate compound is energetically stable, and they are all mechanically stable according to the criteria of elastic stability. For the first time, the calculated elastic constants have allowed us to characterize the elastic anisotropy of acoustic velocity. Additionally, mechanical parameters, such as bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratio σ are deduced by means of Voigt-Reuss-Hill method. It is discovered that, with increasing concentration of Zn, the mechanical moduli and theoretical Vickers hardness of Sr-Zn compounds could be improved. Mechanical anisotropies are discussed by calculating different anisotropic indexes and factors. Finally, calculations on density of states and atomic charge populations are performed to reveal the underlying mechanisms of electronic structure.