First-Principles Modeling of SrTiO3 Based Oxides for Thermoelectric Applications

Using first-principles electronic structure calcu-
lations, 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 nanostruc-
tures 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 ABO3 perovskite oxide materials.