Mechanical and vibrational properties of a and ß MgAl2Ge2 compound Abinitio study

Abstract

MgAl2Ge2 compound is in the hexagonal P63/mmc (α) and trigonal P-3m1 (β) structures. We have been used strass-strain method to predict the second order elastic constants (Cij) and perturbation theory for the vibrational properties of the titled compound within the density functional theory. Our results showed that the compound is satisfy mechanical stability for β-structure confirmed by vibrational calculations. The polycrystalline aggregate behavior estimated using the Cij for mechanically stable β-phase. They are all good agreement with available experimental theoretical data. The calculated phonon dispersion and phonon density of states are also given and discussed.