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Title: Antiferromagnetic, charge-transfer, and pairing correlations in the three-band Hubbard model

Journal Article · · Physical Review, B: Condensed Matter; (United States)
 [1]; ;  [2];  [3]
  1. Department of Physics, University of California, Davis, California 95616 (USA)
  2. Department of Physics, University of California, Santa Barbara, California 93106 (USA)
  3. 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