Thermodynamic phase diagram and thermoelectric properties of LiMgZ (Z = P, As, Bi): ab initio method study

Using first principle calculations based on the density functional theory (DFT), the structural, elastic, electronic, and thermoelectric properties, and thermodynamic stability of the LiMgZ (Z = P, As, Bi) half-Heusler ternary compounds were studied. The results of structural calculations and elastic constants and investigation of the thermodynamic phase diagram represent stability for these compounds in the half-Heusler cubic structure with F4-3 m symmetry. Studying the electronic structure using generalised gradient approximation (GGA) as well as spin-orbit calculations (SOC) reveal that all three LiMgZ (Z = P, As, Bi) structures are non-magnetic semiconductors with an indirect band gap along CYRILLIC CAPITAL LETTER GHE-X direction with values of 1.63, 1.37 and 0.5 eV, respectively. The electron transport behaviours of these materials at various temperatures show that their dimensionless figure of merit (ZT) at the temperature of 200 K reaches its maximum value of 0.813, 0.81 and 0.78 for LiMgP, LiMgAs and LiMgBi, respectively.

Automated summary

Using first principle calculations based on DFT, the study investigated the structural, elastic, electronic, and thermoelectric properties, as well as thermodynamic stability of the LiMgZ (Z = P, As, Bi) half-Heusler ternary compounds. The results showed that these compounds exhibit stability in the half-Heusler cubic structure with F4-3m symmetry, and are non-magnetic semiconductors with indirect band gaps along a specific direction. Additionally, the electron transport behavior of these materials at different temperatures showed optimized ZT values at 200 K.