The grand potential of the one-dimensional extended Hubbard model up to order β5

摘要: Abstract We apply the method of Rojas et al. (J. Math. Phys. 43 (2002) 1390) to calculate high-temperature expansion grand potential one-dimensional (1-D) extended Hubbard model up order β 5 for arbitrary chemical potential. The analytic derived is valid positive and negative values U V . From -expansion we obtain an approximate temperature-dependent quarter-filled band. study behavior thermodynamical quantities, in band, at different phases model. Finally, extend comparison thermodynamic properties 1-D with composite spin-1 (Phys. Rev. B 34 (1986) 487; 40 (1989) 7150) lower temperatures. show that specific heat average energy per spin model, high temperature region, cannot be well approximated by respective functions even strong- regime.