Prospective high thermoelectric performance of the heavily p -doped half-Heusler compound CoVSn

The electronic structure and transport properties of the half-Heusler compound CoVSn are studied systematically by combining first-principles electronic structure calculations and Boltzmann transport theory. The band structure at the valence-band edge is complex with multiple maxima derived from hybridized transition element d states. The result is a calculated thermopower larger than 200μV/K within a wide range of doping concentrations and temperatures for heavily doped p-type CoVSn. The thermoelectric properties additionally benefit from the corrugated shapes of the hole pockets in our calculated isoenergy surfaces. Our calculated power factor S2σ/τ (with respect to an average unknown scattering time) of CoVSn is comparable to that of FeNbSb. A smaller lattice thermal conductivity can be expected from the smaller group velocities of acoustical modes compared to FeNbSb. Overall, good thermoelectric performance for CoVSn can be expected by considering the electronic transport and lattice thermal conductivity.