The fermi linearization scheme for a two-site cluster (dimer) is applied to the extended Hubbard model, including Coulomb interaction between nearest neighbour sites. The partition function and the order parameter, as well as the average double-occupation and local magnetic moment are evaluated. The theory is checked by extended numerical analysis, performed here in the homogeneous case, when pairing is zero, and deriving the explicit temperature and filling dependence of the above quantities. An interesting feature that emerges from such calculations is that the mean-field parameter characteristic of fermi-linearization is capable of describing two different phases, one of which is not present in the conventional Hubbard model. The order parameters corresponding to the two phases are explicitly derived. The novel phase can be ascribed to the n.n. Coulomb interaction, the role of whose strength V is analysed.

Thermodynamics of the Fermi-linearized extended Hubbard Model / Danani, A; Montorsi, Arianna; Rasetti, Mario. - In: INTERNATIONAL JOURNAL OF MODERN PHYSICS B. - ISSN 0217-9792. - 6:(1992), pp. 3529-3541. [10.1142/S0217979292001614]

Thermodynamics of the Fermi-linearized extended Hubbard Model

MONTORSI, Arianna;RASETTI, Mario
1992

Abstract

The fermi linearization scheme for a two-site cluster (dimer) is applied to the extended Hubbard model, including Coulomb interaction between nearest neighbour sites. The partition function and the order parameter, as well as the average double-occupation and local magnetic moment are evaluated. The theory is checked by extended numerical analysis, performed here in the homogeneous case, when pairing is zero, and deriving the explicit temperature and filling dependence of the above quantities. An interesting feature that emerges from such calculations is that the mean-field parameter characteristic of fermi-linearization is capable of describing two different phases, one of which is not present in the conventional Hubbard model. The order parameters corresponding to the two phases are explicitly derived. The novel phase can be ascribed to the n.n. Coulomb interaction, the role of whose strength V is analysed.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/1674203
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo