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Critical Temperatures in the Three‐Band Extended Hubbard Model
Author(s) -
Górski G.,
Mizia J.,
Kucab K.
Publication year - 2000
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200010)221:2<703::aid-pssb703>3.0.co;2-2
Subject(s) - superconductivity , hubbard model , coulomb , condensed matter physics , atomic orbital , physics , electronic band structure , high temperature superconductivity , quantum mechanics , electron
We investigate the three‐band extended Hubbard model for the CuO 2 planes of high‐temperature superconductors. We consider the limit of U = ∞ on Cu atoms and we include the nearest‐neighbor Coulomb repulsion between holes on 2p x , y orbitals of oxygen and holes on 3d x 2– y 2or 3d 3 z 2– r 2orbitals of copper ( V x and V z respectively, with V x > V z ). This leads to the effective negative nearest‐neighbor Coulomb interaction. Numerical analysis of this model reveals the possibility of s‐wave and d‐wave superconductivity arising from the difference Δ V = V z — V x . It was shown that the s‐wave superconductivity is driven by Δ V and is opposed by the Coulomb repulsion on oxygen, U p , while the d‐wave superconductivity is influenced only by the driving force, Δ V . This fact would enable existence of the d‐wave superconductivity in many high temperature superconducting materials.