Attractive interactions from repulsive forces in a multiband Hubbard model

W. H. Stephan, Wolfgang von der Linden, P. Horsch

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An extended multiband Hubbard model of the two-dimensional CuO2 planes of high-Tc superconductors is examined by exact diagonalization of the Hamiltonian for small clusters with periodic boundary conditions. Holes are shown to bind in the limit of large Cu-site and nearest-neighbor Cu-O Coulomb repulsion. A simple explanation of the source of the binding energy is given in this strong-coupling limit. The more realistic case of relatively weak nearest-neighbor repulsion is also examined, and suggestive evidence is presented that the effective attraction will also exist in the thermodynamic limit for this case.
Original languageEnglish
Pages (from-to)2924-2927
Number of pages4
JournalPhysical Review B
Issue number4
Publication statusPublished - 1 Feb 1989

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