Analysis of the electronic nature and transport properties of Co₂CrGe, Co₂FeGe, and Co₂NiGa by computational electronic structure calculations

Abstract

Electronic and thermoelectric properties of the full‐Heusler materials Co2CrGe, Co2FeGe, and Co2NiGa are studied, using first‐principles full potential linearized augmented plane waves method. To treat the exchange correlation, Generalized Gradient Approximation parameterized by PBE‐sol with the inclusion of spin polarization is used. The frequency fluctuation order is continual at 300 K after heating to 3 ps with very small distraction in the atomic structure conforming the structure stability of the studied structures. Also inclusion of spin‐orbit coupling effect on density of states undermines significant change in peaks specially d‐states in the materials and caused a degeneracy. Band structure analysis clarified that states crossing the Fermi level have the importance for enhancing the thermoelectric properties of the materials. The topology of the states indicates a gap at the bulk level, which is the unique character of the heavy elements in the materials Co2CrGe, Co2FeGe, and Co2NiGa. Thermoelectric properties are calculated for a temperature of 300 K using semi‐classical Boltzmann's theory implemented in BoltzTraP code. In these calculations, it is found that these materials favor electron doping with having maximum values of ZT in the n‐type region.