Significant improvement of the Seebeck coefficient of Fe2VAl with antisite defects

In this work we present first principles study of the effect of stoichiometric pairs of antisite defects, V occupying Al site (VAl) and Al occupying V site (AlV), on the electronic structure and Seebeck coefficient of the Fe2VAlHeusler alloy. We show that introduction of these defects opens the bandgap of Fe2VAl, changing it from semi-metal to semiconductor, which results in an increase of the Seebeck coefficient for a range of doping concentrations and temperatures. We calculated Seebeck coefficients at different doping concentrations and temperatures shows good agreement with experimental data.