Structural, electronic and thermoelectric properties of SrTiO₃ ceramic doped by lanthanum using first principles

The Sr₀.9₂La₀.₀₈TiO₃ model compound was studied by means of the first-principles method grounded on the full-potential linearized augmented plane wave with the local orbital method as implement in WIEN2k. The structures, electronic and thermoelectric properties of the model compound are examined. Geometry optimization of Sr₀.9₂La₀.₀₈TiO₃ compound structure reveals the lattice constant of 3.9451 Å, which is the same as un-doped SrTiO₃. The direct bandgap of 2.48 eV (Γ-Γ) was measured from computed electronic band structure and its displayed density of states for Sr₀.9₂La₀.₀₈TiO₃ sample. Transport properties were calculated using BoltzTraP code as implemented in the WIEN2k code. The results were analyzed as a function of the variable temperatures, the density of state and chemical potential. Temperature and density of state variation with transport properties are in the same trend. Chemical potential proves material as n-type via Seebeck coefficient. The thermoelectric performance ZT of 0.05 was obtained at room temperature, while maximum value of 3.79 was recorded at 1200 K.