Electromagnetic response of unconventional superconductors

TL;DR

This paper derives the electromagnetic response of unconventional superconductors, including magneto-optical effects like the Kerr rotation, highlighting differences from conventional superconductors with spontaneous time reversal symmetry breaking.

Contribution

It provides a theoretical derivation of the current response and Kerr effect in nonconventional superconductors with spontaneous magnetization, extending understanding beyond conventional models.

Findings

Derived the current response including magneto-optical terms

Analyzed the Kerr effect in unconventional superconductors

Identified signatures of spontaneous time reversal symmetry breaking

Abstract

We derive the current response to the linearly polarized electromagnetic field with finite frequency and wave vector incident normally on the specular surface of a clean nonconventional superconductor with orbital spontaneous magnetization parallel to the crystal axis and perpendicular to the crystal surface. The result includes the usual part known from the theory of conventional superconductivity and as well the magneto-optical term typical for the superconductors with spontaneous time reversal breaking. As an application of the basic current-field relation we consider the Kerr effect for the rotation of polarization of infrared light reflected from the superconductor surface.