Multiple phase transitions in Pauli limited iron-based superconductors

TL;DR

This paper extends specific heat measurement techniques to multi-band iron-based superconductors, revealing multiple phase transitions at low temperatures and high magnetic fields, aiding the experimental detection of unconventional superconducting states.

Contribution

It introduces a method to identify successive phase transitions in multi-band superconductors using specific heat measurements, advancing the study of unconventional superconductivity.

Findings

Multiple peaks in specific heat indicate successive phase transitions.

Method can verify unconventional superconducting states with non-zero total momentum.

Applicable to iron-based superconductors at low temperatures and high magnetic fields.

Abstract

Specific heat measurements have been successfully used to probe unconventional superconducting phases in one-band heavy-fermion and organic superconductors. We extend the method to study successive phase transitions in multi-band materials such as iron based superconductors. The signatures are multiple peaks in the specific heat, at low temperatures and high magnetic field, which can lead the experimental verification of unconventional superconducting states with non-zero total momentum.