Electronic and thermoelectric properties of nonmagnetic inverse Heusler semiconductors Sc2FeSi and Sc2FeGe

The electronic and thermoelectric properties of two nonmagnetic Hg2CuTi-type or called inverse Heusler semiconductors Sc2FeSi and Sc2FeGe are predicted by using first principles calculations and Boltzmann transport theory. The band gaps of Sc2FeSi and Sc2FeGe are 0.54 eV and 0.60 eV, respectively. Their zero total magneticmoments both satisfy the Mt = Zt-18 while not the Mt = Zt-24 rule. The good thermoelectric properties are achieved under the condition of electron doping. At the room temperature 300 K, the peak value of Seebeck coefficient is −592.02 μVK−1 for Sc2FeSi, and −609.38 μVK−1 for Sc2FeGe by electron doping. The maximum power factor is 48.77(1014 μW cm−1 K−2 s−1) for Sc2FeSi and 47.11(1014 μW cm−1 K−2 s−1) for Sc2FeGe with electron doping concentration −2.29 × 1026 m−3 and −2.42 × 1026 m−3, respectively, which are close to the power factor of well-known thermoelectric material Bi2Te3, indicating their potential applying values for thermoelectric devices.