Highly anisotropic but nodeless gap from a valence-fluctuation pairing mechanism

Conference · Fri Jan 01 00:00:00 EST 1993

DOI:https://doi.org/10.1016/0022-3697(93)90154-J· OSTI ID:6869818

Brandow, B H

We have refined and quantitatively explored a valence-fluctuation pairing mechanism, the finite-U mechanism introduced by Newns. This can provide an s-like (nodeless) gap. We use an Anderson-lattice Hamiltonian, with realistic parameter values derived from photoemission and BIS data. The Landau-Luttinger quasiparticle spectrum and the pairing interaction are obtained from a many-body variational formalism. Adequate pairing attraction is obtained, together with band narrowing (mass enhancement) and an extremely short coherence length, in reasonable agreement with experiment. These fully self-consistent results were obtained with an isotropic approximation to the band structure of a single CuO[sub 2] plane. Now, using a simplified treatment for a more realistic band structure, we find that the gap has strong in-plane anisotropy, although it should probably still remain nodeless. This conclusion is consistent with a variety of data.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6869818
• Report Number(s): LA-UR-93-1088; CONF-930367-1; ON: DE93010738
• Resource Relation: Journal Volume: 54; Journal Issue: 10; Conference: Conference on spectroscopies in novel superconductors, Santa Fe, NM (United States), 17-19 Mar 1993
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER OXIDES
BAND THEORY
ANALYTICAL SOLUTION
ANISOTROPY
ENERGY GAP
HIGH-TC SUPERCONDUCTORS
PAIRING INTERACTIONS
PHOTOEMISSION
SUPERCONDUCTIVITY
CHALCOGENIDES
COPPER COMPOUNDS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EMISSION
INTERACTIONS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SECONDARY EMISSION
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
665410* - Superconductivity- (1992-)