Energy gap, Tc , and pair breaking in the nested-Fermi-liquid model for high- Tc superconductors

Journal Article · Sun Sep 01 04:00:00 EDT 1991 · Journal of Low Temperature Physics; (United States)

DOI:https://doi.org/10.1007/BF00683527· OSTI ID:5167824

Hans, T; Rieck, C T; Fay, D ^[1]

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1. Univ. Hamburg (West Germany)

Eliashberg theory is used to calculate the ratio R = 2{Delta}/k{sub B}T{Tc} for s-wave pairing for a two-dimensional tight-binding band. The pairing is mediated in the authors model by exchange of phonons and higher-frequency excitons which, by themselves, would yield a {Tc} of about 200 K. The additional exchange of an antiferromagnetic spin fluctuation (antiparamagnon) is adjusted to reduce {Tc} to the observed 90 K range. The authors calculate the RPA spin fluctuation propagator self-consistently including the feedback effect of the superconductivity and assuming that only wave vectors near nesting are important. The addition of the antiparamagnon exchange further enhances R, which depends strongly on the band-filling. The resulting values should, however, be compared with a weak-coupling BCS value that, depending on the band structure and band-filling, can be significantly less than 3.5.

• OSTI ID: 5167824
• Journal Information: Journal of Low Temperature Physics; (United States), Journal Name: Journal of Low Temperature Physics; (United States) Vol. 84:5-6; ISSN 0022-2291; ISSN JLTPA
• Country of Publication: United States
• Language: English

Related Subjects

665411* -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BCS THEORY
ENERGY GAP
GORKOV-ELIASHBERG THEORY
HIGH-TC SUPERCONDUCTORS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
TWO-DIMENSIONAL CALCULATIONS