Pseudogaps in Strongly Correlated Metals
Abstract
We generalize the dynamical-mean field (DMFT) approximation by including into the DMFT equations some length scale via a (momentum dependent) ``external'' self-energy \Sigma_k. This external self-energy describes non-local dynamical correlations induced by short-ranged collective SDW-like antiferromagnetic spin (or CDW-like charge) fluctuations. At high enough temperatures these fluctuations can be viewed as a quenched Gaussian random field with finite correlation length. This generalized DMFT+\Sigma_k approach is used for the numerical solution of the weakly doped one--band Hubbard model with repulsive Coulomb interaction on a square lattice with nearest and next nearest neighbour hopping. The effective single impurity problem in this generalized DMFT+\Sigma_k is solved by numerical renormalization group (NRG). Both types of strongly correlated metals, namely (i) doped Mott insulator and (ii) the case of bandwidth W<=U (U - value of local Coulomb interaction) are considered. Densities of states, spectral functions and ARPES spectra calculated within DMFT+\Sigma_k show a pseudogap formation near the Fermi level of the quasiparticle band.
Cite
@article{arxiv.cond-mat/0502612,
title = {Pseudogaps in Strongly Correlated Metals},
author = {M. V. Sadovskii and I. A. Nekrasov and E. Z. Kuchinskii and Th. Pruschke and V. I. Anisimov},
journal= {arXiv preprint arXiv:cond-mat/0502612},
year = {2007}
}
Comments
35 pages, 16 figures