Exploring the structural, optoelectronic, transport, and thermoelectric properties of half-heusler KSrX (X = P, As) for optoelectronic, photovoltaic, and thermoelectric applications

This study provides a comprehensive examination of the structural, electronic, mechanical, and thermoelectric properties of KSrP and KSrAs half-Heusler compounds using density functional theory (DFT) with the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method. Our analysis identifies the Type 2 nonmagnetic phase as the most stable configuration, confirmed by phonon dispersion results with no imaginary frequencies, indicating dynamic stability. The compounds exhibit indirect semiconductor bandgaps along the X–Γ direction as revealed by the band structure and density of states. Elastic property calculations confirm mechanical stability, flexibility and near-isotropic behavior. Thermoelectric properties show high Seebeck coefficients and low lattice thermal conductivities, resulting in a favorable figure of merit that increases with temperature (ZT ∼ 0.8). These results indicate KSrP and KSrAs as promising materials for thermoelectric applications, with potential for improved performance through doping. The optical properties of KSrP and KSrAs show strong visible and UV interactions, making them ideal for optoelectronic and photovoltaic uses. Their plasmonic activity (6–13 eV) supports applications in sensors and UV shielding.