Insights into structural stability, electronic structure, and elastic and thermodynamic properties of A15-type Mo3X (X = Si, Ge, and Sn) compounds based on first-principles predictions

Abstract

In this study, we performed first-principles calculations based on density functional theory to investigate the structure, electronic properties, and elastic and thermodynamic performance of A15-type Mo3X (X = Si, Ge, and Sn) molybdenum-based compounds. The calculated formation enthalpies indicate that all of these Mo3X compounds exhibit thermodynamic stability. The electronic properties of Mo3X, including the band structures, density of states, and electron density difference, indicate that these compounds are metallic. Moreover, the Mo–Mo bonds are covalent whereas the Mo-X bonds are mixed ionic–covalent. The elastic properties of Mo3X compounds were predicted based on the single-crystal and polycrystal elastic moduli. In addition, the anisotropy of elasticity was determined using the elastic anisotropy indexes, three-dimensional surface constructions, and two-dimensional projections. Finally, we explored the thermodynamic parameters, including the Debye temperatures and minimum thermal conductivities. The order of the minimum thermal conductivity was determined as: Mo3Si > Mo3Ge > Mo3Sn.