Superconductors with two critical temperatures

TL;DR

This paper introduces a Ginzburg-Landau model for superconductors exhibiting two distinct second-order phase transitions, revealing a secondary transition at a lower temperature with a significant critical temperature gap.

Contribution

It presents a novel theoretical model for superconductors with two critical temperatures within the Ginzburg-Landau framework, highlighting the conditions for dual phase transitions.

Findings

Identification of two critical temperatures with a maximum 15% difference.

Discovery of a secondary phase transition at a lower temperature.

Model applicable for superconductors with strong Cooper pair interactions.

Abstract

We propose a simple model for superconductors endowed with two critical temperatures, corresponding to two second-order phase transitions, in the framework of the Ginzburg-Landau mean-field theory. For very large Cooper pair self-interaction, in addition to the standard condensation occurring in the Ginzburg-Landau theory, we find another phase transition at a lower temperature with a maximum difference of 15% between the two critical temperatures.