First Principles Modeling of SrTiO3 Based Oxides for Thermoelectric Applications
Using first principles electronic structure calculations, we studied the electronic and thermoelectric properties of SrTiO3 based oxide materials and their nanostructures of SrTiO3/KNbO3, SrTiO3/LaVO3, SrO[SrTiO3] SrO[SrTiO3]2, and SrO[CoO2F] superlattices identifying those nanostructures which possess highly anisotropic electronic bands. We showed recently that highly anisotropic flat and dispersive bands can maximize the thermoelectric power factor, and at the same time they can produce low dimensional electronic transport in bulk semiconductors. Although most of the considered nanostructures show such highly anisotropic bands, their predicted thermoelectric performance is not improved over that of SrTiO3. Besides highly anisotropic character, we emphasize the importance of the large weights of electronic states participating in transport and the small effective mass of charge carriers along the transport direction. These requirements may be better achieved in binary transition metal oxides than in ABO.