Properties of strong-coupled superconductors
By use of Eliashberg equations the system of electrons and phonons with the Einstein spectrum ..cap alpha../sup 2/(..omega..)F(..omega..) = (lambda..cap omega../2)delta(..omega..-..cap omega..) is studied. The orbital and paramagnetic upper critical magnetic fields are obtained in the case of strong electron-phonon coupling lambda (including lambda>>1). For lambda>>1, superconducting parameters at very low temperatures differ remarkably from those near T/sub c/; the crossover takes place at a temperature corresponding to the phonon frequency ..cap omega... For lambdaapprox. >4, at temperatures below about ..cap omega../3 the superconducting correlation length decreases, giving the positive curvature in the temperature dependence of the upper critical field. The coefficients of the Ginzburg-Landau functional are calculated. The absolute value of the specific-heat jump grows with lambda while its relative value drops. For lambdaapprox. >4, the resistivity above T/sub c/ increases linearly with temperature.
- Research Organization:
- International Centre for Theoretical Physics, P.O. Box 586, I-34100 Trieste, Italy
- OSTI ID:
- 6587139
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 38:16; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRITICAL FIELD
ELECTRON-PHONON COUPLING
FUNCTIONALS
FUNCTIONS
GINZBURG-LANDAU THEORY
GORKOV-ELIASHBERG THEORY
MAGNETIC FIELDS
MATHEMATICAL MODELS
PARTICLE MODELS
PHYSICAL PROPERTIES
SPECIFIC HEAT
STRONG-COUPLING MODEL
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES