Ab initio calculation on the structure and elastic properties of a magnesium-lithium alloy

Abstract

Lattice constants, bulk modulus and heat of solution of a Mg7Li1 alloy are calculated by using an ab initio pseudopotential method based on the density function theory and the supercell approach. Lattice constants and bulk modulus at zero pressure are obtained by using the stress calculation and generalized Hooke's law. For exchange and correlation method, the Wigner formula are used and the results are compared with ones using the Perdew and Zunger formula. Calculated lattice constants and bulk modulus are in good agreements with experimental values. We also calculate three kinds of ordered structures on this alloy in order to examine the influence of the structure. The results of three structures are different, respectively, and the influence is discussed from the atomic and electronic structure. The valence charge distribution is decreased around Li atoms. Especially, this region of the low charge distribution spreads in c direction.