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Numerical studies of the generalized spin-one-half Falicov-Kimball model in one and two dimensions

M. ŽONDA1,* , FARKAŠOVSKÝ1, H. ČENČARIKOVÁ1

Affiliation

  1. Institute of Experimental Physics, Slovak Academy of Sciences, Watsonová 47, 041 01 Kosice, Slovakia

Abstract

The extrapolation of small-cluster exact-diagonalization calculations and the Monte-Carlo method is used to study the spinone- half Falicov-Kimball model extended by the spin-dependent Coulomb interaction (J) between the localized f and itinerant d electrons as well as the on-site Coulomb interaction (Uff ) between the localized f electrons. It is shown that in the symmetric case, when the chemical potential μ equals to U (where U is the spin-independent on-site Coulomb interaction between the f and d electrons) the ground-state phase diagram of the model has an extremely simple structure that consists of only two phases, and namely, the charge-density-wave phase (with local f-electron pairs on one of two sublattices of a bipartite lattice) and the spin-densitywave phase. The nonzero temperature studies of the speci_c heat showed that these phases persist also at _nite temperatures. The critical temperature Tc for a transition from the low-temperature ordered phases to the high-temperature disordered one is calculated numerically for various values of J and Uff ..

Keywords

Falicov-Kimball model, Strongly correlated electrons, Charge and spin ordering, Thermodynamics.

Submitted at: April 1, 2008
Accepted at: July 1, 2008

Citation

M. ŽONDA, FARKAŠOVSKÝ, H. ČENČARIKOVÁ, Numerical studies of the generalized spin-one-half Falicov-Kimball model in one and two dimensions, Journal of Optoelectronics and Advanced Materials Vol. 10, Iss. 7, pp. 1704-1708 (2008)