Spin wave mediated non-reciprocal effects in antiferromagnets

TL;DR

This paper demonstrates that spin waves in specific antiferromagnets can induce observable non-reciprocal effects in the microwave region, affecting second harmonic generation and gyrotropic birefringence.

Contribution

It introduces an effective field theory approach to describe how spin waves cause non-reciprocal electromagnetic effects in antiferromagnets, providing calculable susceptibilities.

Findings

Non-reciprocal effects are induced by spin waves in certain antiferromagnets.

Observable signatures include second harmonic generation and gyrotropic birefringence.

The susceptibilities are calculated with parameters of known magnitude.

Abstract

By using an effective field theory for the electromagnetic interaction of spin waves, we show that, in certain antiferromagnets, the latter induce non-reciprocal effects in the microwave region, which should be observable in the second harmonic generation and produce gyrotropic birefringency. We calculate the various (non-linear) susceptibilities in terms of a few parameters the order of magnitude of which is under control.