DRUDE WEIGHT AND DC CONDUCTIVITY OF CORRELATED ELECTRONS

摘要

The Drude weight D and the de conductivity sigma(dc)(T) of strongly correlated electrons are investigated theoretically. Analytic results are derived for the homogeneous phase of the Hubbard model at d = infinity, and for spinless fermions in this limit with 1/d corrections systematically included to lowest order. It is found that sigma(dc)(T) is finite for all T > 0, displaying Fermi-liquid behavior, sigma(dc) proportional to 1/T-2, at low temperatures. The validity of this result for finite dimensions is examined by investigating the importance of umklapp scattering processes and vertex corrections. A finite dc conductivity for T > 0 is argued to be a generic feature of correlated lattice electrons in not too low dimension. [References: 39]