Thermoelectric properties, optimal doping levels and high figure of merit in Cobalt-based Half/Full Heusler alloys by First-Principles calculations

Abstract

We present the thermoelectric properties of Co2MnPb, Co2MnSn, CoMnPb, and CoMnSn Heusler alloys, with the effect of doping on the alloys and the resulting high figure of merit. From the Boltzmann transport equations, we calculated the transport coefficient of each of these Heusler alloys. These help in determining the electrical conductivity, Seebeck coefficient, thermal conductivity per relaxation time and the figure of merit for both the up-spin and down-spin of the alloys. From our results, the down-spin electrical conductivity per relaxation time showed improved results along the p-type carrier when compared with that of the n-type carrier. The up-spin Seebeck coefficient showed a more significant effect along the p-type in Co2MnPb, Co2MnSn, and CoMnSn, whereas it has sharp peaks along the n-type carrier for CoMnPb Heusler alloys. The combinations of the constituent elements result in a high figure of merit in the alloys, which will improve if appropriately doped.