Correlations of superconducting fluctuations in a two-gap system

TL;DR

This paper analytically derives spatial correlation functions for gap fluctuations in a two-band superconductor, highlighting how intra- and interband interactions influence coherence lengths and fluctuation behavior near the phase transition.

Contribution

It provides a novel analytical framework for understanding spatial correlations in two-gap superconductors, emphasizing the roles of multiple coherence channels.

Findings

Two distinct correlation lengths govern gap fluctuations.

Both channels are crucial at the phase transition point.

The relative contributions depend on temperature and system parameters.

Abstract

We derive analytically the spatial correlation functions for gap fluctuations in two-band scenario with intra- and interband pair-transfer interactions. These functions demonstrate the changes in spatial functionality due to the presence of two channels of coherency described by the divergent and finite correlation lengths. Even at the phase transition point both channels are essential for two-band superconductivity. Generally their relative contributions depend on the temperature and system parameters.