Frustrated multiband superconductivity

TL;DR

This paper explores how multiband superconductors can undergo multiple phase transitions involving frustrated phase configurations as temperature varies, especially with odd numbers of repulsive interband interactions.

Contribution

It reveals the conditions under which frustrated phase transitions occur in multiband superconductors, highlighting the role of the number of bands and interband interactions.

Findings

Multiple phase transitions with temperature in multiband superconductors.

Transitions involve frustrated configurations of order parameters.

Signatures include slope changes in gap temperature dependence.

Abstract

We show that a clean multiband superconductor may display one or several phase transitions with increasing temperature from or to frustrated configurations of the relative phases of the superconducting order parameters. These transitions may occur when more than two bands are involved in the formation of the superconducting phase and when the number of repulsive interband interactions is odd. These transitions are signalled by slope changes in the temperature dependence of the superconducting gaps.