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Exact solution of the extended Hubbard model in the atomic limit on the Bethe lattice

F. MANCINI1, F. P. MANCINI2, A. NADDEO1,*

Affiliation

  1. Dipartimento di Fisica “E. R. Caianiello”- Unità CNISM di Salerno, Università di Salerno, 84081 Baronissi (SA), Italy
  2. Dipartimento di Fisica and Sezione I.N.F.N., Università di Perugia, Via A. Pascoli, 06123 Perugia, Italy

Abstract

We study the phase diagram at finite temperature of a system of Fermi particles on the sites of the Bethe lattice with coordination number z and interacting through onsite U and nearest-neighbor V interactions. This is a physical realization of the extended Hubbard model in the atomic limit. By using the equations of motion method, we exactly solve the model. For an attractive intersite potential, we find, at half filling, a phase transition towards a broken particle-hole symmetry state. The critical temperature, as a function of the relevant parameters, has a re-entrant behavior as already observed in the equivalent spin-1 Ising model on the Bethe lattice..

Keywords

Hubbard model, Bethe lattice.

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

Citation

F. MANCINI, F. P. MANCINI, A. NADDEO, Exact solution of the extended Hubbard model in the atomic limit on the Bethe lattice, Journal of Optoelectronics and Advanced Materials Vol. 10, Iss. 7, pp. 1688-1693 (2008)