First-principle investigation of optoelectronic and thermoelectric properties in XYGe (X = Li, K) half-Heusler compounds at different exchange correlation functional

In this study, the structural, electronic, thermodynamic, elastic, optical, and thermoelectric properties of XYGe (X = Li, K) half-Heusler compounds are thoroughly investigated using generalized gradient approximation (GGA-PBE), local density approximation (LDA), Wu – Cohen (WC), and TB-mBJ exchange potentials. The density functional theory (DFT) inside the full potential − linearized augmented plane wave (FP-LAPW) approach encapsulated in Wien2k is used to investigate these properties. The band structure and DOS results confirm semiconducting nature of the compounds. The thermodynamic and elastic research findings show that the compounds are thermally and mechanically stable. The various optical properties are examined, and the results obtained indicate that the materials are a promising option for optoelectronic devices. The various thermoelectric properties are also investigated. The figure of merit (ZT) of 3.28 for KYGe under LDA approach and 3.34 for LiYGe under TB-mBJ approach were obtained at 300 K temperature.