Effective modelling of the Seebeck coefficient of Fe2VAl

Previous first-principles calculations have failed to reproduce many of the key thermoelectric features of Fe2VAl, e.g. the maximum values of the Seebeck coefficientSand its asymmetry with respect to the chemical potential. Also, previous theoretical predictions suggested that the pseudo band gap of Fe2VAl switches from indirect to direct upon doping. In this work, we report first-principles calculations that correctly reproduce the experimentally measured thermoelectric properties of Fe2VAl. This is achieved by adding a larger HubbardUterm to V atoms than to Fe atoms and including a scissors operator afterwards. As a result, bulk Fe2VAl is modelled as a gapless semiconductor with maximumSvalues of 76 and -158 μV/K forp- andn-type, respectively, which agree well with the experimental measurements.