First-Principle Calculations to Investigate the Elastic, Thermoelectric, and Electronic Performances of XRhSn (X = V, Nb, Ta) Half-Heusler Compounds

Half-Heusler alloy is an excellent thermoelectric material. In our studies, we studied and compared the elastic, electronic, and thermoelectric properties of three half-Heusler alloys, VRhSn, NbRhSn, and TaRhSn by combining the Boltzmann transport theory and deformation potential theory. Additionally, we used Slack’s model to compute the lattice thermal conductivity. We found that n-type compound TaRhSn has ZT values of 2.13 with 1.22 × 1020 cm−3 at 1200 K; NbRhSn has ZT values of 1.41 with 1.26 × 1020 cm−3 at 1100 K, respectively. These discoveries suggest that TaRhSn and NbRhSn compounds may become new high-temperature thermoelectric materials. The effective masses of TaRhSn and NbRhSn conduction bands are only 0.38 me and 0.33 me, respectively, causing the higher carrier mobilities and relaxation times. At 1200 K, the lattice thermal conductivities of TaRhSn and NbRhSn compounds are only 3.60 W/mK and 3.41 W/mK, respectively; this may be caused by strong phonon–phonon interaction.