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

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 Mo 3 X (X = Si, Ge, and Sn) molybdenum-based compounds. The calculated formation enthalpies indicate that all of these Mo 3 X compounds exhibit thermodynamic stability. The electronic properties of Mo 3 X, 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 Mo 3 X 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: Mo 3 Si > Mo 3 Ge > Mo 3 Sn. • Mo 3 X (X = Si, Ge, Sn) compounds are thermodynamically and mechanically stable. • Mo–Mo and Mo-X bonds in Mo 3 X are mixed ionic–covalent bonds. • Elastic anisotropy follows the order of: Mo 3 Sn > Mo 3 Si > Mo 3 Ge.