"Destruction" of the Fermi surface due to pseudogap fluctuations in strongly correlated systems
E. Z. Kuchinskii, I. A. Nekrasov, M. V. Sadovskii
Institute for Electrophysics, RAS Ural Branch, 620016 Ekaterinburg, Russia
PACS: 71.10.Fd, 71.10.Hf, 71.27.+a, 71.30.+h, 74.72.-h
Abstract
We generalize the dynamical-mean field theory (DMFT)
by including into the DMFT equations dependence on correlation length of
pseudogap fluctuations via additional (momentum dependent) self-energy
Σ k. This 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+Σ 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
is solved by numerical renormalization group (NRG).
Both types of strongly correlated metals, namely (i) doped Mott
insulator and (ii) the case of bandwidth (U - value of
local Coulomb interaction) are considered.
Calculating profiles of spectral densities for different parameters of the
model we demonstrate the qualitative picture of Fermi surface "destruction"
and formation of "Fermi arcs" due to pseudogap fluctuations in qualitative
agreement with ARPES experiments. "Blurring" of the Fermi surface is
enhanced with the growth of the Coulomb interaction.