First-principles Modelling of SrTiO3 based Oxides for Thermoelectric Applications

TL;DR

This study uses first-principles calculations to analyze SrTiO3-based oxides and nanostructures, focusing on their electronic and thermoelectric properties, and identifies key factors influencing thermoelectric performance.

Contribution

It demonstrates that highly anisotropic electronic bands alone do not guarantee improved thermoelectric performance in SrTiO3 nanostructures.

Findings

Highly anisotropic bands are common but do not enhance thermoelectric performance.

Large weights of electronic states and small effective masses are crucial for better thermoelectric properties.

Binary transition metal oxides may outperform ABO3 perovskites in thermoelectric applications.

Abstract

Using first-principles electronic structure calculations, we studied the electronic and thermoelectric properties of SrTiO3 based oxide materials and their nanostructures 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 ABO3 perovskite oxide materials.