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Author Carbotte, J.P.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ SUPERCONDUCTORS ♦ GORKOV-ELIASHBERG THEORY ♦ BARIUM OXIDES ♦ BCS THEORY ♦ COPPER OXIDES ♦ CRITICAL FIELD ♦ ELECTRON-PHONON COUPLING ♦ ENERGY GAP ♦ LANTHANUM OXIDES ♦ LEAD ♦ NIOBIUM ♦ OPTICAL PROPERTIES ♦ PHONONS ♦ REVIEWS ♦ SPECTRAL DENSITY ♦ STRONTIUM OXIDES ♦ TRANSITION TEMPERATURE ♦ TUNNEL EFFECT ♦ VANADIUM SILICIDES ♦ YTTRIUM OXIDES ♦ ALKALINE EARTH METAL COMPOUNDS ♦ BARIUM COMPOUNDS ♦ CHALCOGENIDES ♦ COPPER COMPOUNDS ♦ DOCUMENT TYPES ♦ ELEMENTS ♦ FUNCTIONS ♦ LANTHANUM COMPOUNDS ♦ MAGNETIC FIELDS ♦ METALS ♦ OXIDES ♦ OXYGEN COMPOUNDS ♦ PHYSICAL PROPERTIES ♦ QUASI PARTICLES ♦ RARE EARTH COMPOUNDS ♦ SILICIDES ♦ SILICON COMPOUNDS ♦ SPECTRAL FUNCTIONS ♦ STRONTIUM COMPOUNDS ♦ THERMODYNAMIC PROPERTIES ♦ TRANSITION ELEMENT COMPOUNDS ♦ TRANSITION ELEMENTS ♦ VANADIUM COMPOUNDS ♦ YTTRIUM COMPOUNDS ♦ Condensed Matter Physics- Superconductivity
Abstract The author reviews some of the important successes achieved by Eliashberg theory in describing the observed superconducting properties of many conventional superconductors. Functional derivative techniques are found to help greatly in understanding the observed deviations from BCS laws. Approximate analytic formulas with simple correction factors for strong-coupling corrections embodied in the single parameter {ital T}{sub {ital c}}/{omega}{sub ln} are also found to be very helpful. Here {ital T}{sub {ital c}} is the critical temperature and {omega}{sub ln} is an average boson energy mediating the pairing potential in Eliashberg theory. In view of the discovery of high-{ital T}{sub {ital c}} superconductivity in the copper oxides, results in the very strong coupling limit of {ital T}{sub {ital c}}/{omega}{sub ln}{similar to}1 are also considered, as is the asymptotic limit when {ital T}{sub {ital c}}/{omega}{sub ln}{r arrow}{infinity}. This case is of theoretical interest only, but it is nevertheless important because simple analytic results apply that give insight into the more realistic strong-coupling regime. A discussion more specific to the oxides is included in which it is concluded that some high-energy boson-exchange mechanism must be operative, with, possibly, some important phonon contribution in some cases. A more definitive application of boson-exchange models to the oxides awaits better experimental results.
ISSN 00346861
Educational Use Research
Learning Resource Type Article
Publisher Date 1990-10-01
Publisher Place United States
Journal Reviews of Modern Physics
Volume Number 62
Issue Number 4


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