2 research outputs found
Densities of states of the Falicov-Kimball model off half filling in infinite dimensions
An approximate analytical scheme of the dynamical mean field theory (DMFT) is
developed for the description of the electron (ion) lattice systems with
Hubbard correlations within the asymmetric Hubbard model where the chemical
potentials and electron transfer parameters depend on an electron spin (a sort
of ions). Considering a complexity of the problem we test the approximation in
the limiting case of the infinite- spinless Falicov-Kimball model. Despite
the fact that the Falicov-Kimball model can be solved exactly within DMFT, the
densities of states of localized particles have not been completely
investigated off half filling. We use the approximation to obtain the spectra
of localized particles for various particle concentrations (chemical
potentials) and temperatures. The effect of a phase separation phenomenon on
the spectral function is considered.Comment: 9 pages, 11 figures, submitted to Phys. Rev.
Mott transition in the asymmetric Hubbard model at half-filling within dynamical mean-field theory
We apply the approximate analytic methods to the investigation of the band
structure of the asymmetric Hubbard model where the chemical potentials and
electron transfer parameters depend on the electron spin (type of
quasiparticles). The Hubbard-I and alloy-analogy approximations are the
simplest approximations which are used. Within the alloy-analogy approximation,
the energy band of particles does not depend on the transfer parameter of
particles of another sort. It means that the gap in the spectrum opens at the
critical value that is the same in two different limiting cases: the
Falicov-Kimball model and the standard Hubbard model. The approximate analytic
scheme of the dynamical mean-field theory is developed to include into the
theory the scattering of particles responsible for the additional mechanism
(due to the transfer of particles of another sort) of the band formation. We
use the so-called GH3 approach that is a generalization of the Hubbard-III
approximation. The approach describes the continuous Mott transition with the
value dependent on a ratio of transfer parameters of different
particles.Comment: 10 pages, 10 figure