ELECTRONIC STRUCTURE AND OPTICAL CONDUCTIVITY OF THE FULL HEUSLER ALLOY Fе2TiSn
Full Heusler alloy Fe2SnTi is of interest as a cheap and environmentally friendly thermoelectric material for the mere conversion of heat to electricity. Recently, a significant number of works have been published in the literature, where its electronic structure was studied by the density functional theory method. However, the scatter of the data obtained is so wide, from the presence of a pseudogap to the prediction of the forbidden band with a width of about 1 eV, that it is impossible to draw unambiguous conclusions about the electronic properties of this compound. In this work, we performed high-precision calculations of the electronic structure of the Heusler alloy Fe2SnTi using the GW0 method and found that it is a semiconductor with a band gap of 0.34 eV. To explain the experiments on measuring the optical conductivity at which a metallic response was observed, various defect structures were investigated.