2001/06/28 by Jacek Wojtkiewicz, J. Wojtkiewicz, R. Lemański +1 · 3 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.64.233103
4 pages, RevTeX, 2 figures, references added, typos corrected
arxiv created 2001/06/28 · openalex publication_date 2001/11/08 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Two-dimensional spinless Falicov-Kimball model (FKM) with correlated hopping is studied perturbatively in the limit of large on-site Coulomb interaction U. In the half filled case (i.e., \ensuremathρi+\ensuremathρe=1, where \ensuremathρi,\ensuremathρe are densities of ions and electrons, respectively) the effective Hamiltonian in spin variables is derived up to terms proportional to U^\ensuremath-3. Unlike the simplest FKM case, it contains odd parity terms (resulting from the correlated hopping) in addition to even parity ones. The ground-state phase diagram of the effective Hamiltonian is examined in the (a/t,h) plane, where a/t is a parameter characterizing strength of the correlated hopping and h is a difference of chemical potentials of two sorts of particles present in the system. It appears to be asymmetric with respect to the change \stackrel\ensuremath→h\ensuremath-h and an additional ordered phase is found for a certain interval of a/t.