  In search of new prospects for thermoelectric materials, using ab-initio
calculations and semi-classical Boltzmann theory, we have systematically
investigated the electronic structure and transport properties of 18-valence
electron count cobalt based half-Heusler alloys with prime focus on CoVSn,
CoNbSn, CoTaSn, CoMoIn, and CoWIn. The effect of doping on transport properties
has been studied under the rigid band approximation. The maximum power factor,
S$^2\sigma$, for all systems is obtained on hole doping and is comparable to
the existing thermoelectric material CoTiSb. The stability of all the systems
is verified by phonon calculations. Based on our calculations, we suggest that
CoVSn, CoNbSn, CoTaSn, CoMoIn and CoWIn could be potential candidates for high
temperature thermoelectric materials.
