Unusual thermodynamical and transport signatures of short coherence length superconductors: A BCS Bose-Einstein crossover approach

TL;DR

This paper models thermodynamic and transport properties of short coherence length superconductors using a BCS Bose-Einstein crossover approach, revealing unusual signatures and behaviors consistent with experimental data.

Contribution

It introduces a BCS Bose-Einstein crossover theory that satisfies key physical constraints and applies it to explain properties of short coherence length superconductors.

Findings

Predicted behavior of Knight shift, superfluid density, and specific heat.

Identified strong coupling limit characteristics.

Supported by comparison with experimental data on organic and high Tc superconductors.

Abstract

In this paper we present predictions for thermodynamic and transport properties of a BCS Bose-Einstein crossover theory, below Tc, which theory satisfies the reasonable constraints that it yield (i) the Leggett ground state and (ii) BCS theory at weak coupling and all temperatures. The nature of the strong coupling limit is inferred, along with the behavior of the Knight shift, superfluid density, and specific heat. Comparisons with existing data on short coherence length superconductors, such as organic and high Tc systems, are presented, which provide some support for the present picture.