On the possibility of thermoelectricity in half Heusler XRuSb (X = V, Nb, Ta) materials: A first principles prospective

In this study, we explored the electronic and thermoelectric properties of three semiconducting half Heusler compounds XRuSb (X = V, Nb, Ta) using density functional theory and semi-classical Boltzmann transport theory. We calculated the Seebeck coefficient and the electrical, electronic, and lattice thermal conductivity with changes in the temperature. These materials were identified as good thermoelectric materials with narrow band gaps and fiat electronic bands in the valence band. The Seebeck coefficient and electronic thermal conductivity increased with temperature. The electrical conductivity and lattice thermal conductivity decreased as the temperature increased. The calculations indicated that p-type doping had a higher power factor than n-type doping. The spin orbit coupling (SOC) effect on the thermoelectric properties was also considered. The relaxation time (tau) decreased as the temperature increased. The maximum value for the figure of merit was equal to 0.13, which was achieved by VRuSb.