Thermoelectric transport coefficients of n-doped CaTiO3, SrTiO3 and BaTiO3: A theoretical study

Boltzmann transport equations and density functional theory calculations were employed to calculate the thermoelectric transport coefficients of CaTiO3, SrTiO3 and BaTiO3. It was found that BaTiO3 has the largest Seebeck coefficient and power factor. Then the transport coefficients were analyzed using the 'Tight Binding Model'. The band narrowing, caused by the increasing lattice constants from CaTiO3 to BaTiO3, was the main reason for the increasing Seebeck coefficients and the decreasing electrical conductivity. The calculated electrical conductivity and electronic thermal conductivity were in line with the Wiedemann-Franz law and the Lorenz factor was determined to be 2.45 for these oxides as degenerate semiconductors. Our theoretical results are helpful for seeking high performance thermoelectric oxides.