2002/11/21 by J. Batle, Josep Amengual i Batle, M. Casas +17
Chemistry · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Superconductivity (cond-mat.supr-con) #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/0211456
17 pages including 4 figures. To be published in Cond. Matt. Theories Vol. 18, Ed. Joao da Providencia ((Nova Science Publisher, Inc., N. Y., 200?)
openalex publication_date 2002/11/21 · arxiv created 2002/11/28 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We review efforts to unify both the Bardeen, Cooper and Schrieffer (BCS) and Bose-Einstein condensation (BEC) pictures of superconductivity. We have finally achieved this in terms of a "complete boson-fermion (BF) model" (CBFM) that reduces in special cases to all the main continuum (as opposed to "spin") statistical theories of superconductivity. Our BF model is "complete" in the sense that not only two-electron (2e) but also two-hole (2h) Cooper pairs (CPs) are allowed in arbitrary proportions. In contrast, BCS-Bogoliubov theory--which can also be considered as the theory of a mixture of kinematically independent electrons, 2e- and 2h-CPs--allows only equal, 50%-50%, mixtures of the two kinds of CPs. This is obvious from the perfect symmetry about μ, the electron chemical potential, of the well-known Bogoliubov v2(ε) and u2(ε) coefficients, where ε is the electron energy. The CBFM is then applied to see: a) whether the BCS model interaction for the electron-phonon dynamical mechanism is sufficient to predict the unusually high values of Tc (in units of the Fermi temperature) of ≃ 0.01-0.1 exhibited by the so-called ``exotic'' superconductors \citeBrandow in both 2D and 3D--relative to the low values of \lesssim 10-3 more or less correctly predicted by BCS theory for conventional, elemental superconductors; and b) whether it can at least suggest, if not explain, why "hole superconductors" have higher Tc's.