Remarkable thermoelectric power factors achieved by regulating strain-induced polarizations of SrNbxTi1-xO3

Strong electron-correlations shed lights on improvements for conventional thermoelectric materials used in electric power generations from temperature gradients and solid-state refrigeration. Here, we report remarkable thermoelectric power factors achieved in micrometer-thick SrNbxTi1-xO3 films with strong electron correlations when coupling the carriers with strain-induced lattice-polarons. SrNbxTi1-xO3 films with effectively preserved lattice distortions exhibit orbital anisotropy from the cross-plane charge ordering, as demonstrated by polarization dependent near edge X-ray absorption fine structures. The coulomb-correlations between the lattice-polarons and electron-carriers improve the change of system entropy during carrier transportations and significantly enhance the Seebeck coefficient. The achieved maximum thermoelectric power factor of 2,642 uWcm-1K-2 for micrometer-thick SrNb0.2Ti0.8O3 films exceeds the ones reported, while their zT values are even larger than the best thermoelectric materials reported for low-temperature usages. It is believed to be applicable in in-plane thermoelectric power generator or thermal sensors.