Intrinsic and extrinsic origins of the polar Kerr effect in a chiral p-wave superconductor

TL;DR

This paper clarifies that the polar Kerr effect in chiral p-wave superconductors like Sr2RuO4 has both intrinsic and extrinsic origins, with disorder-induced extrinsic effects likely dominating experimental observations.

Contribution

It distinguishes between intrinsic and extrinsic contributions to the polar Kerr effect, emphasizing the dominance of extrinsic effects in experiments.

Findings

Extrinsic (disorder-induced) effects dominate the polar Kerr effect.

Intrinsic effects also contribute but are less significant.

Clarifies the origin of the Kerr effect in chiral superconductors.

Abstract

Recently, the measurement of the polar Kerr effect (PKE) in the quasi two-dimensional superconductor Sr2RuO4, which is motivated to observe the chirality of px + i py-wave pairing, has been reported. We clarify that the PKE has intrinsic and extrinsic (disorder-induced) origins. The extrinsic contribution would be dominant in the PKE experiment.