Theoretical prediction of the structural, elastic, electronic, and thermodynamic properties of the Nowotny-Juza LiMgAsxSb1-x alloy

We present a theoretical study of the structural, elastic, electronic and thermodynamic properties of the LiMgAsxSb1-x alloy in alpha-phase, from the density functional theory framework (DFT) and the pseudopotentials with planes waves approach, using the alchemical mixing approximation available in the ABINIT code. The lattice parameter, bulk modulus and elastic constants for the parent compounds LiMgAs and LiMgSb were found to agree reasonably with the available experimental and theoretical data. The compositional dependence of the lattice constant, bulk modulus, the elastic constants (C-ij) and energy gap shows deviations from Vegard's law with differentiation of bowing parameters. We found that the LiMgAsxSb1-x alloy in alpha-phase are indirect semiconductors (Gamma-X) for all concentrations. The origins of the gap bowing parameters were also examined using the approach of Zunger and co-workers. The variation of some thermodynamic proprieties as a function of the temperature for different Arsenic concentration have been predicted and discussed such as unit cell volume, Bulk modulus, Debye temperature, heat capacity at volume constant and thermal expansion coefficient. (C) 2019 Elsevier B.V. All rights reserved.