ABSTRACT 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 Г-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.

中文翻译：

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LiMgZ (Z = P, As, Bi) 的热力学相图和热电性质：从头算方法研究

摘要使用基于密度泛函理论 (DFT) 的第一性原理计算，研究了 LiMgZ (Z = P, As, Bi) 半赫斯勒三元化合物的结构、弹性、电子和热电性质以及热力学稳定性。结构计算和弹性常数的结果以及热力学相图的研究表明这些化合物在具有 F4-3 m 对称性的半赫斯勒立方结构中的稳定性。使用广义梯度近似 (GGA) 和自旋轨道计算 (SOC) 研究电子结构表明，所有三个 LiMgZ (Z = P, As, Bi) 结构都是非磁性半导体，沿 Г-X 具有间接带隙方向的值分别为 1.63、1.37 和 0.5 eV。