Spin fluctuations and high-temperature superconductivity in the copper oxides

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:6988304

Monthoux, P H

The author reports studies of spin-fluctuation-induced superconductivity in the antiferromagnetically correlated copper oxide high temperature superconductors. The spin fluctuation mechanism is first studied within a weak coupling approximation. It is shown that the retarded interaction between quasiparticles on a 2D square lattice induced by the exchange of antiferromagnetic paramagnons leads uniquely to a transition to a superconducting state with d[sub x][sup 2][minus]y[sup 2] symmetry. The effective quasiparticle interaction responsible for superconductivity possesses considerable structure in both momentum and frequency space, and it is shown, by explicit calculations, that if one wishes to obtain quantitatively meaningful results it is essential to allow for that structure in solving the full integral equations which determine the superconducting transition temperature and the superconducting properties. With a spin excitation spectrum and a quasiparticle-paramagnon coupling determined by fits to normal state experiments, the author obtains high transition temperatures and energy gap behaviors comparable to those measured for YBa[sub 2]Cu[sub 3]O[sub 7], YBa[sub 2]Cu[sub 3]O[sub 6.63], and La[sub 1.85]Sr[sub 0.15]CuO[sub 4]. The author then studies the influence of strong coupling effects, and high temperature superconductivity is obtained. This requires the solution of the Eliashberg equations taking full account of the momentum and frequency dependence of the effective interaction; approximations commonly used for phonon-induced superconductivity fail to yield quantitatively meaningful results.

• Research Organization: Illinois Univ., Urbana, IL (United States)
• OSTI ID: 6988304
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
665411 -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANGULAR MOMENTUM
ANTIFERROMAGNETIC MATERIALS
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
COUPLING
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HIGH-TC SUPERCONDUCTORS
INTERMEDIATE COUPLING
J-J COUPLING
MAGNETIC MATERIALS
MATERIALS
OXIDES
OXYGEN COMPOUNDS
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
SPIN
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS