Current-sensitive Hall effect in a chiral-orbital-current state*

Chiral orbital currents (COC) underpin a novel colossal magnetoresistance (CMR) in ferrimagnetic Mn₃Si₂Te₆ [1]. Here we report the Hall effect in the COC state which exhibits the following unprecedented features: (1) A sharp, current-sensitive peak in the magnetic field dependence of the Hall resistivity; (2) An unusually large Hall angle reaching up to 0.15 (comparable to the highest values yet reported); and (3) A current-sensitive scaling relation between the Hall conductivity σ_xy and the longitudinal conductivity σ_xx, namely, σ_xy ∝ σ_xx^α with a ranging between 3 and 5, which is both sensitive to external current and exceptionally large compared to α < 2 typical of most solids. These anomalies point to a giant, current-sensitive Hall effect that is unique to the COC state. We argue that a magnetic field induced by the fully developed COC combines with the applied magnetic field to exert the greatly enhanced transverse force on charge carriers, which dictates the novel Hall responses. The COC Hall effect expands the existing set of Hall phenomena and suggests that a more general approach to magneto-transport in solids is needed.