Many-body derivation of quasiparticle bands and effective interactions of fermions in CuO sub 2 layers

Journal Article · Sun Jul 01 04:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.307· OSTI ID:6551796

Entel, P; Zielinski, J ^[1]

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1. Theoretische Tieftemperaturphysik, Universitaet-GH-Duisburg, 4100 Duisburg (West Germany)

We discuss normal-state properties and the phase diagram of high-{Tc} copper oxide superconductors on the basis of a five-states model (one {ital d} state and two bonding and two nonbonding {ital p} states per unit cell) for interacting electrons in a single CuO{sub 2} layer. In particular, quasiparticle bands and densities of states have been derived by applying a generalized Hubbard-I scheme to the five-states model and to the reduced three-states model. We find that in both cases and for realistic values of model parameters the insulating gap opens between an antibonding band of almost pure {ital p} character and the antibonding band of mainly {ital d} character. The insulating state is thus of the charge-transfer type and introducing holes into the {ital p}-like antibonding band metallizes the system. This would mean that in the presence of an attractive interaction at least a part of the Cooper pairs are formed out of only weakly correlated {ital p}-type quasiparticles. Insight of the normal-state behavior can be gained from a discussion of the spectral distribution of strongly correlated and more localized {ital d} electrons among mobile {ital p} electrons or holes. The work is supplemented by a brief discussion of the residual interactions among quasiparticles and by a comparison of our model with more strong-coupling models like the {ital t}-{ital J} model. Finally, we present formal solutions for the Green's functions by using a more refined decoupling scheme. The influence of the resulting lifetime effects and Kondo-type features on the quasiparticle spectra is briefly discussed.

• OSTI ID: 6551796
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:1; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BAND THEORY
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DIAGRAMS
FERMIONS
FUNCTIONS
GREEN FUNCTION
HIGH-TC SUPERCONDUCTORS
INTERACTIONS
KONDO EFFECT
MANY-BODY PROBLEM
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
QUASI PARTICLES
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS