Anomalous skew-scattering nonlinear Hall effect and chiral photocurrents in {\it PT}-symmetric antiferromagnets

TL;DR

This paper uncovers a novel nonlinear Hall effect in PT-symmetric antiferromagnets that arises from the cooperation of Berry curvature and skew-scattering, producing helicity-dependent photocurrents and offering new ways to probe antiferromagnetic order.

Contribution

It introduces the anomalous skew-scattering nonlinear Hall effect (ASN), a PT-even phenomenon that dominates low-frequency nonlinear Hall responses in PT-symmetric antiferromagnetic metals.

Findings

ASN produces helicity-dependent photocurrents.

ASN dominates low-frequency nonlinear Hall effects.

The effect enables probing of antiferromagnetic order.

Abstract

Berry curvature and skew-scattering play central roles in determining both the linear and nonlinear anomalous Hall effects. Yet in {\it PT}-symmetric antiferromagnetic metals, Hall effects from either intrinsic Berry curvature mediated anomalous velocity or the conventional skew-scattering process individually vanish. Here we reveal an unexpected nonlinear Hall effect that relies on both Berry curvature and skew-scattering working in cooperation. This anomalous skew-scattering nonlinear Hall effect (ASN) is {\it PT}-even and dominates the low-frequency nonlinear Hall effect for {\it PT}-symmetric antiferromagnetic metals. Surprisingly, we find that in addition to its Hall response, ASN produces helicity dependent photocurrents, in contrast to other known {\it PT}-even nonlinearities in metals which are helicity blind. This characteristic enables to isolate ASN and establishes new photocurrent tools to interrogate the antiferromagnetic order of {\it PT}-symmetric metals.