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Title:Spin fluctuations and high-temperature superconductivity in the copper oxides
Author(s):Monthoux, Philippe Henri
Doctoral Committee Chair(s):Pines, David
Department / Program:Physics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Physics, Condensed Matter
Abstract: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 $\rm d\sb{x\sp2-y\sp2}$ 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 $\rm YBa\sb2Cu\sb3O\sb7,$ $\rm YBa\sb2Cu\sb3O\sb{6.63},$ and $\rm La\sb{1.85}Sr\sb{0.15}CuO\sb4.$
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.
Issue Date:1992
Rights Information:Copyright 1992 Monthoux, Philippe Henri
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9236545
OCLC Identifier:(UMI)AAI9236545

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