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FIZIKA A 17 (2008) 2 , 59-66
 
GROUND STATE ENERGY OF 2D EXTENDED HUBBARD MODEL FOR FINITE SIZE SYSTEM WITH
AN EXACT DIAGONALIZATION
S. HARIRa,1, M. BENNAIa,c,2 and Y. BOUGHALEBa,b,d
aLaboratoire de Physique de la Matière Condensée, Faculté des
Sciences Ben M'Sik,
Université Hassan II-Mohammedia, Casablanca, Morocco
bLPMC, Faculté des Sciences d' El Jadida, Université Chouaib Doukkali, Morocco
cGroupement National de Physique des Hautes Energies, LabUFR-PHE, Rabat, Morocco
dHassan II Academy of Sciences and Technology, Morocco
E-mail addresses:1harirsaid@gmail.com,
2bennai_idrissi@yahoo.fr
Received 20 July 2007; Revised manuscript received 29 May 2008
Accepted 3 September 2008 Online 17 October 2008
Using an exact analytical diagonalization for an extended Hubbard model, we
study the first nearest-neighbour repulsion effect on the behaviour of a
two-dimensional system of finite size at low density of electrons. The obtained
results show that the introduction of the nearest-neighbour off-site interaction
allows the correlation effects to become more remarkable and to play an
essential role in the electron dynamics, and this off-site interaction
encourages the formation of double occupancies.
PACS numbers: 71.10, -W.75.10.Jm, 72.15.Nj
UDC 538.915, 538.935
Keywords: extended Hubbard model, ground state, double occupation, gap energy
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