High-Tc superconductivity via superpropagators revisited

• Published in: Physica. C, Superconductivity Superconductivity, 2008-07, Vol.468 (13), p.949-954
• Main Author: Malik, G.P.
• Format: Article
• Language: English
• Subjects: (e–e)-, (h–h)-, and (e–h)-pairs; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Extended Cooper problem; High-Tc superconductivity; Multi-component superconductors; Physics; Superconductivity; Theory and models of superconducting state
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2008.03.002

We revisit our earlier paper because it was perceived in some quarters to be based on a formulation that took into account the electron-pairs (e-pairs), but not the hole-pairs (h-pairs). Through a more comprehensive study of the basic equation on which our earlier work was based, we present here temperature-generalized equations for the Bethe–Salpeter amplitudes for Cooper pairs (CPs) of the (e–e), (h–h), and (e–h/h–e) varieties (our earlier paper seemed to deal with only the first category of pairs). We then show that solution of the (e–e) or the (h–h) equation, at T=0, yields a pair of pure imaginary binding energies (W); this result is in agreement with the one obtained long ago by Thouless, by Abrikosov et al., by Schrieffer, and others, and signifies that both the e-pairs and the h-pairs have been taken into account in our work. A salient feature of our approach is that it determines the all-important Tc and Hc in the limit of vanishing W whereas, in the BCS theory, Tc is obtained in the limit gap→0, and Hc is determined via the condensation energy of the CPs.