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 . This external self-energy describes nonlocal dynamical correlations induced by the short-ranged collective spin density wave–like antiferromagnetic spin (or the charge density wave–like charge) fluctuations. At high enough temperatures these fluctuations can be viewed as a quenched Gaussian random field with a finite correlation length. This generalized approach is used for the numerical solution of the weakly doped one-band Hubbard model with repulsive Coulomb interaction on a square lattice with the nearest and the next nearest neighbor hopping. The effective single impurity problem in this generalized is solved by the numerical renormalization group. Both types of the strongly correlated metals, namely: (i) The doped Mott insulator and (ii) the case of the bandwidth (—value of the local Coulomb interaction) are considered. The densities of states, the spectral functions, and the angle resolved photoemission spectra calculated within the show a pseudogap formation near the Fermi level of the quasiparticle band.
5 More- Received 4 March 2005
DOI:https://doi.org/10.1103/PhysRevB.72.155105
©2005 American Physical Society