Strain dependence of the thermoelectric properties of perovskite MgSiO3: A first principles study

Abstract

Using first-principles density functional theory based approach, we investigate the tunability of the thermoelectric properties of perovskite MgSiO3. We find that the thermoelectric properties are strongly correlated with the electronic structure and can, therefore, be modulated with uni-axial tensile and compressive strains. Key thermoelectric parameters, such as the Seebeck coefficient (S), show non-monotonic behavior, displaying large shifts with the application of 1% uni-axial tensile strain. The relevance of this small strain value also appears in structural distortion of the oxygen octahedra and band convergence in the electronic band structure. The band structure modifications also introduce a strong strain dependence of the relaxation time, as defined within the deformation potential approach. As a result, an improvement of up to 35% is observed in zT with the application of 1% tensile strain. Our results highlight a possible new route to improving thermoelectric performance in perovskite oxide thermoelectrics.