Studying the Seebeck coefficient of Fe2VAl compound in the high temperature region

The full-Heusler Fe2VAl compound is an emerging thermoelectric material with non-magnetic ground state. Here, the temperature dependence of Seebeck coefficient (S) of Fe2VAl is studied in the temperature region 320-620 K. The experimental value of S is found to be -119 µ V/K at T=320 K, then the absolute values of S decrease as the temperature increases. At T=620 K, the value of S is found to be -26 µ V/K. In order to understand the behavior of measured Seebeck coefficient, first-principles electronic structure calculations and transport properties calculations are carried out. The dispersion curve and density of states are computed with density functional theory (DFT) by using modified Becke-Johnson (mBJ) potential. The calculated band gap of the compound is ∼0.22 eV, which gives the good agreement with experimental value of band gap. The temperature dependence of S of Fe2VAl is obtained by using BoltzTraP package. The calculated and experimental values of S are compared and found to match reasonably good, but at higher temperature slight deviation is observed.