1990/10/01 by J. P. Ćarbotte · 1 voice · 10 citations
Physics and Astronomy · Materials Science · #Physics of Superconductivity and Magnetism #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials
paper · doi:10.1103/revmodphys.62.1027
openalex publication_date 1990/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
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 \fracTc\ensuremathωln are also found to be very helpful. Here Tc is the critical temperature and \ensuremathωln is an average boson energy mediating the pairing potential in Eliashberg theory. In view of the discovery of high-Tc superconductivity in the copper oxides, results in the very strong coupling limit of \fracTc\ensuremathωln\ensuremath∼1 are also considered, as is the asymptotic limit when \fracTc\ensuremathωln\ensuremath→\ensuremath∞. 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.