Anomalous Skew-Scattering Nonlinear Hall Effect and Chiral Photocurrents in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="script">PT</mml:mi></mml:math>-Symmetric Antiferromagnets
Da Ma, Arpit Arora, Giovanni Vignale, Justin C. W. Song
Abstract
Berry curvature and skew scattering play central roles in determining both the linear and nonlinear anomalous Hall effects. Yet in $\mathcal{PT}$-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 $\mathcal{PT}$ even and dominates the low-frequency nonlinear Hall effect for $\mathcal{PT}$-symmetric antiferromagnetic metals. Surprisingly, we find that in addition to its Hall response, ASN produces helicity dependent photocurrents, in contrast to other known $\mathcal{PT}$-even nonlinearities in metals that are helicity blind. This characteristic enables us to isolate ASN and establishes new photocurrent tools to interrogate the antiferromagnetic order of $\mathcal{PT}$-symmetric metals.