GREEN'S FUNCTIONS OF INFINITE-$U$ ASYMMETRIC HUBBARD
MODEL: FALICOV-KIMBALL LIMIT
Author(s): I.V.Stasyuk, O.B.Hera (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine)
The asymmetric Hubbard model is used in investigating the lattice gas of the moving particles of two types. The model is considered within the dynamical mean-field method. The effective single-site problem is formulated in terms of the auxiliary Fermi-field. To solve the problem an approximate analytical method based on the irreducible Green's function technique is used. This approach is tested on the Falicov-Kimball limit (when the mobility of ions of either type is infinitesimally small) of the infinite-$U$ case of the model considered. The dependence of chemical potentials on concentration is calculated using the one-particle Green's functions, and different approximations are compared with the exact results obtained thermodynamically. The densities of states of localized particles are obtained for different temperatures and particle concentrations. The phase transitions are investigated for the case of the Falicov-Kimball limit in different thermodynamic regimes.
Key words: asymmetric Hubbard model, Falicov-Kimball model,
dynamical mean-field theory, Green's functions, phase transitions
PACS: 71.10.Fd, 05.30.Fk, 05.70.Fh
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