First-principles study on thermoelectric properties of half-Heusler compounds CoMSb (M = Sc, Ti, V, Cr, and Mn)

We have performed systematic density functional calculations and evaluated thermoelectric properties (Seebeck coefficient and anomalous Nernst coefficient) of half-Heusler compounds CoMSb (M = Sc, Ti, V, Cr, and Mn). The carrier concentration dependence of the Seebeck coefficient in nonmagnetic compounds is in good agreement with experiments. We found that the half-metallic ferromagnetic CoMnSb shows a large anomalous Nernst effect originating from Berry curvature near the Brillouin zone boundary. These results help us understand the mechanism of a large anomalous Nernst coefficient and give us a clue to design high performance magnetic thermoelectric materials.