Iron disulfide compound: a promising thermoelectric material

Abstract

As a promising material for thermoelectric devices and alternative energy applications, the electronic structures and thermoelectric properties of FeS2 with both pyrite (p-FeS2) and marcasite (m-FeS2) phases are systematically investigated by using the Boltzmann transport equation combined with ab initio calculations. By adopting a more precise hybrid functional for electronic calculations, the values of the band gap being close to the experimental values are obtained. A feature of narrow band gaps and dense electronic states near Fermi level supports the p-FeS2 and m-FeS2 as thermoelectric (TE) materials. The TE factors that depend on chemical potential, temperature, and hole-doping concentrations are calculated and discussed for the two phases. The m-FeS2 structure possesses superior TE property in both n-type and p-type regions. From the analysis of the effect of hole-doping concentrations and temperatures on TE properties in both structures, it is found that a high temperature and high hole-doping concentrations are helpful for improving the TE efficiency. The calculated power factors showed high values for both structures, which classified them as good thermoelectric materials.