First-principles calculation of lattice thermal conductivity and thermoelectric figure of merit in ferromagnetic half-Heusler alloy CoMnSb

Abstract

Half-Heusler (HH) alloys are an important and well-studied class of thermoelectric, magnetic, and spintronic materials. However, few studies have reported on thermal conductivity of magnetic HH alloys. In this study, we have performed first-principles calculation of the thermoelectric properties of a magnetic HH alloy CoMnSb. The lattice thermal conductivity of CoMnSb was found to be smaller than typical nonmagnetic HH alloys (CoTiSb, CoZrSb). The reason for this was found to be the small group velocity and relaxation time of acoustic phonons. Moreover, we estimated the electronic thermal conductivity and power factor, and finally, we evaluated the thermoelectric figure of merit ZT of CoMnSb.