Charge-transfer and magnetic-pairing mechanisms in the extended Hubbard model of high- Tc oxides

Journal Article · Wed Aug 01 00:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.2200· OSTI ID:6359478

Wagner, J; Muramatsu, A; Hanke, W ^[1]

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1. Physikalisches Institut, Universitaet Wuerzburg, Am Hubland, D-8700 Wuerzburg (Federal Republic of Germany)

Charge-transfer and spin-interaction-mediated pairing is derived within a strong-coupling expansion for an extended multiband Hubbard model describing Cu-O--based superconductors. We include both intrasite ({ital U}{sub {ital d}},{ital U}{sub {ital p}}) and intersite ({ital U}{sub {ital p}{ital d}}) Coulomb repulsions. The basic carriers are oxygen-hole quasiparticles in {ital p}{sub {sigma}} orbitals. They interact via a charge-transfer mechanism driven by {ital U}{sub {ital p}{ital d}} and via a magnetic mechanism, which is due to a constructive interplay between the enhanced (by {ital U}{sub {ital p}{ital d}}) Kondo (Cu-O) exchange and the superexchange of the Cu spins. Within the BCS limit we find that {ital U}{sub {ital p}{ital d}} enhances the relative weight of {ital s} versus {ital d}-wave pairing, with the dominance of {ital s}-wave pairing for large transfer energies {Delta}={ital E}{sub {ital p}}{minus}{ital E}{sub {ital d}} and at low-to-intermediate doping. The charge-transfer-induced coupling is negligible in this large-{Delta} limit. In the small-{Delta} limit it induces a 10--20 % enhancement of the BCS {Tc}.

• OSTI ID: 6359478
• Journal Information: Physical Review, B: Condensed Matter; (USA), Vol. 42:4; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
HIGH-TC SUPERCONDUCTORS
MATHEMATICAL MODELS
BCS THEORY
CHARGE TRANSPORT
COPPER OXIDES
COUPLING
HOLES
KONDO EFFECT
OXYGEN
CHALCOGENIDES
COPPER COMPOUNDS
ELEMENTS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
656100* - Condensed Matter Physics- Superconductivity
360204 - Ceramics
Cermets
& Refractories- Physical Properties