Condensed Matter Physics, 2001, vol. 4, No. 1(25), p. 85-92, English
DOI:10.5488/CMP.4.1.85

Title: STRONG COUPLING HARTREE-FOCK APPROXIMATION IN THE DYNAMICAL MEAN-FIELD THEORY
Author(s): A.M.Shvaika (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine)

In the limit of infinite spatial dimensions, a thermodynamically consistent theory, which is valid for arbitrary value of the Coulombic interaction ($U<\infty$), is built for the Hubbard model when the total auxiliary single-site problem exactly splits into four subspaces with different vacuum states''. Some analytical results are given for the Hartree-Fock approximation when the 4-pole structure for Green's function is obtained: two poles describe contribution from the Fermi liquid component, which is ferromagnetic and dominant for small electron and hole concentrations (overdoped case'' of high-$T_{\rm c}$'s), whereas other two describe contribution from the non-Fermi liquid, which is antiferromagnetic and dominant close to half filling (underdoped case'').

Key words: dynamical mean-field theory, Hartree-Fock approximation, Hubbard model, (anti)ferromagnetism, strong coupling
PACS: 71.10.Fd, 71.15.Mb, 05.30.Fk, 71.27.+a

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