Antiferromagnetic, charge-transfer, and pairing correlations in the three-band Hubbard model
- Department of Physics, University of California, Davis, California 95616 (USA)
- Department of Physics, University of California, Santa Barbara, California 93106 (USA)
- Department of Physics, University of California, Irvine, California 92717 (USA)
The CuO{sub 2} sheets common to the superconducting cuprates are believed to be characterized by a charge-transfer gap in their insulating antiferromagnetic state. The three-band Hubbard model with an on-site Cu Coulomb interaction {ital U}{sub {ital d}}, which is large compared to the difference in energy {var epsilon} between the O and Cu sites, provides a basic model for such a system. We have carried out Lanczos and Monte Carlo studies of a CuO{sub 2} lattice described by a three-band Hubbard model. For {ital U}{sub {ital d}} large compared with {var epsilon}, and {var epsilon} comparable to or larger than the bandwidth of the lower hole band, we find strong antiferromagnetic correlations and evidence for a charge-transfer gap at a filling of one hole per Cu. The antiferromagnetic correlations decrease with either hole or electron doping, and we see that the additional holes go primarily on the O sites, while additional electrons go onto the Cu sites. For large values of the intersite Cu-O Coulomb interaction {ital V}, the hole-doped system exhibits a charge-transfer instability. As {ital V} is reduced, this is reflected as a peak in the charge-transfer susceptibility near {var epsilon}+2{ital V}{approx}{ital U}{sub {ital d}}, which we find is washed out by the strong Cu-O hybridization at realistic values of {ital V}. Attractive pairing interactions are found in both the {ital d}-wave and extended {ital s}{sup *}-wave channels near the antiferromagnetic boundary.
- DOE Contract Number:
- FG03-85ER45197
- OSTI ID:
- 5661822
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 44:2; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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