Thermoelectric transport coefficients of n-doped CaTiO _3, SrTiO _3 and BaTiO _3: A theoretical study

摘要

Boltzmann transport equations and density functional theory calculations were employed to calculate the thermoelectric transport coefficients of CaTiO _3, SrTiO _3 and BaTiO _3. It was found that BaTiO _3 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 CaTiO _3 to BaTiO _3, 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 WiedemannFranz 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.