Intralayer versus interlayer pairing in the copper oxide superconductors: The three- and four-layer problems

Journal Article · Wed Jan 01 00:00:00 EST 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.45.415· OSTI ID:7276300

Liu, S H ^[1]; Klemm, R A ^[2]

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1. Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6032 (United States)
2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

We have analyzed the possible superconducting states of a model layered superconductor with {ital N} conducting layers in a unit cell, for {ital N}=3 and 4, in the presence of both intralayer and interlayer pairing interactions. In case all layers are identical, the system has the same behavior as one-layer and two-layer systems, namely that pure intralayer pairing interaction stabilizes an {ital s}-wave state with equal and isotropic gaps in all {ital N} quasiparticle bands, while interlayer pairing produces both singlet and triplet paired states with anisotropic gap functions. The singlet state is always energetically more stable than the triplet state. The analysis can be easily extended to nonidentical layers. As one example, a model for YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} consisting of two CuO{sub 2} layers in a unit cell separated by a layer of CuO chains is discussed. It is shown that the system reduces to an effective two-layer model, due to the large difference in electronic energy states between the planes and the chains. The chains are most likely nonsuperconducting. In another example, we show that Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} can be reduced to an effective three-layer system. Recent tunneling data can be understood on the basis of this model.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7276300
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 45:1; 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
PAIRING ENERGY
BCS THEORY
ELECTRONIC STRUCTURE
ENERGY GAP
FERMI LEVEL
HAMILTONIANS
LAYERS
QUASI PARTICLES
BINDING ENERGY
ENERGY
ENERGY LEVELS
MATHEMATICAL OPERATORS
QUANTUM OPERATORS
SUPERCONDUCTORS
665411* - Basic Superconductivity Studies- (1992-)
360204 - Ceramics
Cermets
& Refractories- Physical Properties