Observation of Rashba-related and switchable anomalous Hall effect in an antiferromagnetic metal

The anomalous Hall effect (AHE) lies at the heart of a major research field of contemporary condensed matter physics, in which geometrical features of wavefunctions in momentum space control physical observables. Here, we report the observation of an AHE in AgCrSe₂, a layered triangular lattice metal that lacks inversion symmetry, and has a sizeable antiferromagnetic coupling between Cr spin 3/2 moments in adjacent layers. In particular, we find that AgCrSe₂ exhibits an anomalous Hall resistivity of up to 3 µΩ cm at 2 K, comparable to the largest magnitude observed in any antiferromagnetic system to date. We further demonstrate that the anomalous Hall response in thin layers can be switched on and off by an applied ionic gate, or by controlling the direction of an applied magnetic field. Preliminary theory model suggests the observed AHE is driven by Berry curvature that correlates closely with the Rashba spin-orbit coupling.