Third-order phase transition and superconductivity in thin films

TL;DR

This paper introduces a new mean field solution in BCS theory indicating third-order superconducting phase transitions in thin films, with critical temperature increasing as thickness decreases and no isotope effect.

Contribution

It presents a novel mean field solution predicting third-order phase transitions in layered superconductors, expanding understanding of superconductivity in reduced dimensions.

Findings

Critical temperature increases with decreasing film thickness.

Superconducting transition is of third order.

No isotope effect observed.

Abstract

We have found a new mean field solution in the BCS theory of superconductivity. This unconventional solution indicates the existence of superconducting phase transitions of third order in thin films, or in bulk matter with a layered structure. The critical temperature increases with decreasing thickness of the layer, and does not exhibit the isotope effect. The electronic specific heat is a continuous function of temperature with a discontinuity in its derivative.