Kerr effect as evidence of gyrotropic order in the cuprates - revisited

TL;DR

This paper clarifies that Kerr effect signals in cuprates are due to point-group symmetry rather than time-reversal symmetry breaking, challenging previous interpretations linking Kerr response to gyrotropic order.

Contribution

It revisits the theoretical basis of Kerr effect interpretation, emphasizing the role of point-group symmetry over time-reversal symmetry in cuprates.

Findings

Kerr response vanishes in time-reversal invariant systems obeying Onsager relations.

Experimental Kerr signals in cuprates are linked to point-group symmetry, not gyrotropic order.

Previous assumptions connecting Kerr effect to gyrotropy are incorrect.

Abstract

Recent analysis has confirmed earlier general arguments that the Kerr response vanishes in any time-reversal invariant system which satisfies the Onsager relations. Thus, the widely cited relation between natural optical activity (gyrotropy) and the Kerr response, employed in Hosur \textit{et al}, Phys. Rev. B \textbf{87}, 115116 (2013), is incorrect. However, there is increasingly clear experimental evidence that, as argued in our paper, the onset of an observable Kerr-signal in the cuprates reflects point-group symmetry rather than time-reversal symmetry breaking.