Thermoelectric Signatures of Time-Reversal Symmetry Breaking States in Multiband Superconductors

TL;DR

This paper explores how broken time-reversal symmetry in multiband superconductors leads to distinctive magnetic and electric responses under inhomogeneous heating, enabling identification of specific superconducting states.

Contribution

It demonstrates that local and nonstationary heating can produce measurable magnetic and electric signatures unique to time-reversal symmetry breaking states.

Findings

Heating induces magnetic fields sensitive to domain walls and anisotropy.

Nonstationary heating generates electric fields and charge imbalance across bands.

Methods can distinguish between $s+is$ and $s+id$ superconducting states.

Abstract

We show that superconductors with broken time-reversal symmetry have very specific magnetic and electric responses to inhomogeneous heating. A local heating of such superconductors induces a magnetic field with a profile that is sensitive to the presence of domain walls and crystalline anisotropy of superconducting states. A nonstationary heating process produces an electric field and a charge imbalance in different bands. These effects can be measured and used to distinguish $s+is$ and $s+id$ superconducting states in the candidate materials such as Ba$_{1-x}$K$_x$Fe$_2$As$_2$.