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Title: Phenomenology of the valence-fluctuation pairing mechanism: {Tc} systematics of cuprates, and evidence for this mechanism in other superconductors

Abstract

The phenomenology of the cuprate superconductors is unconventional in many respects, in addition to the high {Tc}`s. A number of these features have recently been explained, qualitatively and even semi-quantitatively, by means of a valence-fluctuation mechanism. They now examine the extent to which this mechanism can account, at a qualitative level, for the {Tc} systematics of the many known cuprate superconductors. They find that this mechanism is consistent with some major features of the {Tc} systematics: the strong dependence on the hole-doping concentration x, the strong correlation with the Madelung potential of the apical oxygens, and a strong dependence on the number of apical oxygens per planar copper ion. They also argue that the same mechanism should be operating (together with phonons) in a number of other superconductors, in particular in the other exotic superconductors of Uemura. The evidence is that typical features of these exotics include extremely short coherence length, very high (and often T{sup 2}) normal-state resistivity, a highly anomalous form of H{sub c2}(T), a large London penetration depth, and an often obvious suitability for representation by an Anderson lattice form of model Hamiltonian. The frequently-encountered cluster and/or reduced-dimensionality aspects are argued to be features which help tomore » justify the latter form of model Hamiltonian. 81 refs.« less

Authors:
 [1]
  1. Los Alamos National Lab., NM (United States). Center for Nonlinear Studies
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
32065
Resource Type:
Journal Article
Journal Name:
International Journal of Modern Physics B
Additional Journal Information:
Journal Volume: 8; Journal Issue: 27; Other Information: PBD: 15 Dec 1994
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 66 PHYSICS; HIGH-TC SUPERCONDUCTORS; MATHEMATICAL MODELS; CERAMICS; COPPER OXIDES; SUPERCONDUCTIVITY; CRITICAL FIELD

Citation Formats

Brandow, B.H. Phenomenology of the valence-fluctuation pairing mechanism: {Tc} systematics of cuprates, and evidence for this mechanism in other superconductors. United States: N. p., 1994. Web. doi:10.1142/S0217979294001664.
Brandow, B.H. Phenomenology of the valence-fluctuation pairing mechanism: {Tc} systematics of cuprates, and evidence for this mechanism in other superconductors. United States. doi:10.1142/S0217979294001664.
Brandow, B.H. Thu . "Phenomenology of the valence-fluctuation pairing mechanism: {Tc} systematics of cuprates, and evidence for this mechanism in other superconductors". United States. doi:10.1142/S0217979294001664.
@article{osti_32065,
title = {Phenomenology of the valence-fluctuation pairing mechanism: {Tc} systematics of cuprates, and evidence for this mechanism in other superconductors},
author = {Brandow, B.H.},
abstractNote = {The phenomenology of the cuprate superconductors is unconventional in many respects, in addition to the high {Tc}`s. A number of these features have recently been explained, qualitatively and even semi-quantitatively, by means of a valence-fluctuation mechanism. They now examine the extent to which this mechanism can account, at a qualitative level, for the {Tc} systematics of the many known cuprate superconductors. They find that this mechanism is consistent with some major features of the {Tc} systematics: the strong dependence on the hole-doping concentration x, the strong correlation with the Madelung potential of the apical oxygens, and a strong dependence on the number of apical oxygens per planar copper ion. They also argue that the same mechanism should be operating (together with phonons) in a number of other superconductors, in particular in the other exotic superconductors of Uemura. The evidence is that typical features of these exotics include extremely short coherence length, very high (and often T{sup 2}) normal-state resistivity, a highly anomalous form of H{sub c2}(T), a large London penetration depth, and an often obvious suitability for representation by an Anderson lattice form of model Hamiltonian. The frequently-encountered cluster and/or reduced-dimensionality aspects are argued to be features which help to justify the latter form of model Hamiltonian. 81 refs.},
doi = {10.1142/S0217979294001664},
journal = {International Journal of Modern Physics B},
number = 27,
volume = 8,
place = {United States},
year = {1994},
month = {12}
}