2004/09/30 by E. J. Nicol, J. P. Carbotte, J. P. Ćarbotte · 2 citations
Materials Science · Physics and Astronomy · #Anisotropy #BCS theory #Band gap #Condensed matter physics #Coupling (piping) #Coupling parameter #Diagonal #Dimensionless quantity #Iron-based superconductors research #Jump #London penetration depth #Materials science #Penetration depth #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Scattering #Superconductivity #Superconductivity in MgB2 and Alloys #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.71.054501
published as Phys. Rev. B 71, 054501 (2005) · 20 pages, 14 figures, final version accepted in PRB
arxiv created 2005/01/16 · openalex publication_date 2005/02/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Eliashberg theory is used to investigate the range of thermodynamic properties possible within a two-band model for s-wave superconductivity and to identify signatures of its two-band nature. We emphasize dimensionless BCS ratios [those for the energy gaps, the specific heat jump, and the negative of its slope near Tc, the thermodynamic critical field Hc(0), and the normalized slopes of the critical field and the penetration depth near Tc], which are no longer universal even in weak coupling. We also give results for temperature-dependent quantities, such as the penetration depth and the energy gap. Results are presented both for microscopic parameters appropriate to MgB2 and for variations away from these. Strong coupling corrections are identified and found to be significant. Analytic formulas are provided that show the role played by the anisotropy in coupling in some special limits. Particular emphasis is placed on small interband coupling and on the opposite limit of no diagonal coupling. The effect of impurity scattering is considered, particularly for the interband case.