Stabilization of critical temperature with respect to repulsion in strong-coupled superconductors

Abstract

It is shown that the Eliashberg’s equations (EE) have two kinds of solutions for the critical temperature Tc. The solution of the first kind leads to the traditional smooth dependence of Tc on the value of the Coulomb pseudopotential μ*. This dependence has been extensively studied in literature. The second kind of solutions manifests as quantized critical temperatures appearing at finite values of μ* but not depending on its magnitude. Such solutions are only possible for strong-coupled superconductors. Thus, the dependence Tc(μ*) in the mean-field approximation is a many-valued function. In the vicinity where the traditional solution approaches a quantized solution the mean-field approximation fails and the system fluctuationally switches to another stable mean-field branch. This process results in appearance of flat regions in the Tc(μ*) dependence.

Source-reported materials — not catalogue approval

Similar papers