Electronic fitness function, effective mass and thermoelectric properties of Rh-based (-ScTe; -TiSb; -VSn) alloys for thermoelectric generator applications

Abstract

The electronic fitness function, effective mass, and other thermoelectric properties of novel Rh(ScTe; TiSb; VSn) half-Heusler-like alloys are predicted from first-principles calculations in conjunction with Boltzmann’s Transport Theory. The calculated power factor, Seebeck coefficient, electrical conductivity, and thermal conductivity were obtained via the constant relaxation time approach implemented in the BolzTraP code. Six doping levels (3 each for electrons and holes) were used to determine the transport properties in the present work. The present results revealed that RhScTe is a non-magnetic semiconductor alloy with a narrow bandgap of 0.40 eV. Whereas, RhTiSb and RhVSn are semi-metals with no bandgaps. Besides, corresponding excess holes per unit cell at all doping levels were observed, which implies that RhScTe and RhTiSb are p-type semiconductors. In Particular, for RhScTe, we observed an increasing power factor with temperature; at 800K, the power factor is slightly above 60μWcm−1K−2s−1. At room temperature, the compound exhibits a power factor of 24μWcm−1K−2s−1 at a carrier concentration of 1×1022cm−3 which is similar to a reference p-type FeNbSb compound.