Observation of Temperature-Independent Anomalous Hall Effect in Thin Bismuth from Near Absolute Zero to 300 K Temperature

We report our discovery of a temperature-independent anomalous Hall effect (AHE) from 15 mK to 300 K temperature occurring in a pure bismuth transport device whose average thickness is 68 nm. This surprising behavior is accompanied with an expected temperature-dependent longitudinal resistance consistent with semimetallic bismuth. However, it surprisingly showed no hint of a magnetoresistance for magnetic fields between ±30 T. Even though bismuth is a diamagnetic material that a priori does not break time-reversal symmetry, our analysis of the reconstructed conductivities points toward the AHE to be of the intrinsic type that does not emanate from magnetic impurities. Finally, as pure bismuth has been shown numerically to host a Berry curvature at its surface that breaks inversion symmetry, we propose it as a possible explanation for the temperature-independent AHE observed here.