https://doi.org/10.1140/epjb/e2010-00031-8
Different orderings in the narrow-band limit of the extended Hubbard model on the Bethe lattice
1
Dipartimento di Fisica “E. R. Caianiello", Università degli Studi di Salerno, Via Ponte don Melillo, 84084 Fisciano (SA), Italy
2
Unità CNISM di Salerno, Via Ponte don Melillo, 84084 Fisciano (SA), Italy
3
Laboratorio Regionale SuperMat, CNR-INFM, Via Ponte don Melillo, 84084 Fisciano (SA), Italy
4
I.N.F.N. Sezione di Perugia, Via A.
Pascoli, 06123 Perugia, Italy
Corresponding author: fpmancini@sa.infn.it
Received:
28
September
2009
Revised:
30
November
2009
Published online:
27
January
2010
We present the exact solution of a system of Fermi particles living on the sites of a Bethe lattice with coordination number z and interacting through on-site U and nearest-neighbor V interactions. This is a physical realization of the extended Hubbard model in the atomic limit. Within the Green's function and equations of motion formalism, we provide a comprehensive analysis of the model and we study the phase diagram at finite temperature in the whole model's parameter space, allowing for the on-site and nearest-neighbor interactions to be either repulsive or attractive. We find the existence of critical regions where charge ordering (V > 0) and phase separation (V < 0) are observed. This scenario is endorsed by the study of several thermodynamic quantities.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010