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Theoretical studies on effective interactions in two‐band system
Author(s) -
Nagao Hidemi,
Kawabe Hiroyuki
Publication year - 2005
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.20737
Subject(s) - hubbard model , limit (mathematics) , superconductivity , electronic correlation , physics , condensed matter physics , electron , quantum mechanics , quantum , matrix (chemical analysis) , electronic band structure , statistical physics , chemistry , mathematics , mathematical analysis , chromatography
We investigate effective interactions in a two‐dimensional two‐sublattice system by using a two‐band Hubbard model. We present a t ‐matrix approach for two‐dimensional two‐sublattice system and derive expressions of effective interactions by using the t ‐matrix approach. Expressions of the effective exchange integral in the Heisenberg model are also approximately derived. The results suggest that two‐band superconductivity appears in the limit of an almost‐empty or almost‐filled band and strongly electron–electron correlation in two‐band systems. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005