Computational prediction of high thermoelectric performance in MPtSn (M = Ti, Zr, and Hf) half-Heusler compounds by first-principle study

Abstract

The excellent thermoelectric efficiencies of half-Heusler compounds mainly originate from their distinctive crystal structure, high-thermal stability, and outstanding electrical transport performance. In this work, we investigate the elastic constants, electronic structure, and thermoelectric properties of MPtSn (M = Ti, Zr, and Hf) compounds using semi-classical Boltzmann transport theory and deformation potential model. The predicted maximum ZT value of n-type TiPtSn reaches up to 2.19 at the optimal electron carrier concentration of 5.98 × 1020 cm−3 at 1000 K. This ZT value is much higher than the previously experimental reported value. The electronic structure and phonon dispersion of the p-type HfPtSn compound suggest that doping at the Pt position can decrease the lattice thermal conductivities and modify the carrier concentrations. It is expected that these investigations could provide valuable guidance for exploring high-performance thermoelectric materials.