Thermopower and Hall Effect in Correlated Metals and Doped Mott-Hubbard Insulators: DMFT Approximation

Abstract

We present brief review of theoretical studies of thermopower and Hall effect in the Hubbard model within the DMFT approximation for correlated metal and Mott insulator (considered as prototype cuprate superconductor) for different concentrations of current carriers. Analysis is performed within standard DMFT approximation. For Mott insulator we consider the typical case of partial filling of the lower Hubbard band (hole doping). We calculate the dependence of the Hall coefficient and thermopower on doping level and determine the critical concentration of carriers corresponding to sign change of these quantities. A significant temperature dependence of the Hall coefficient and an anomalous dependence of thermopower on temperature (significantly different from linear typical for the usual metals) is obtained. The role of disorder scattering is analyzed on qualitative level. We also perform a comparison of our theoretical results with some known experiments on doping dependence of Hall number in the normal state of YBCO and Nd-LSCO, demonstrating rather satisfactory agreement of theory and experiment. Violation of electron-hole symmetry leads to the appearance of the relatively large interval of band-fillings (close to the half-filling) where thermopower and Hall effects have different signs. We propose a certain scheme allowing to determine the number of carriers from ARPES data and perform semi-quantitative estimate of both thermopower and Hall coefficient using the usual DFT calculations of electronic spectrum.