Doping dependence of thermopower and thermoelectricity in strongly correlated materials

The search for efficient semiconductor thermoelectrics has been greatly aided by theoretical modeling of electron and phonon transports in bulk materials and nanocomposites. Recent experiments have studied thermoelectric transport in thermoelectrics that are “strongly correlated” and derived by doping Mott insulators. Here a unified theory of electrical and thermal transport in the atomic and “Heikes” limit is applied to understand recent experiments on sodium cobaltate and other doped Mott insulators at room temperature and above. For optimal electron filling, a broad class of narrow-bandwidth correlated materials is shown to have thermoelectric power factors as high as in the best semiconductors.