The structural, elastic, electronic and optical properties of MgCu under pressure: A first-principles study

The effect of pressure on the structural, elastic and electronic properties of the inter metallic compound MgCu with a CsCl-type structure have been investigated using ab initio technique. The optical properties have been studied under normal pressure. We have carried out the plane-wave pseudopotential approach within the framework of the first-principles density functional theory (DFT) implemented within the CASTEP code. The calculated structural parameters show a good agreement with the experimental and other theoretical results. The most important elastic properties including the bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratio nu of the cubic-type structure MgCu are determined under pressure by using the Voigt-Reuss-Hill (VRH) averaging scheme. The results show that the MgCu intermetallic becomes unstable under pressure more than 15 GPa. The study of Cauchy pressure and Pugh's ratio exhibit brittle nature of MgCu at ambient condition and the compound is transformed into ductile nature with the increase of pressure. For the first time we have investigated the electronic and optical properties of MgCu. The electronic band structure reveals metallic conductivity and the major contribution comes from Cu-3d states. Reflectivity spectrum shows that the reflectivity is high in the ultraviolet region up to 72 eV.