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Chiral orbital currents (COC) underpin a novel colossal magnetoresistance in ferrimagnetic Mn₃Si₂Te₆. 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, and (2) A current-sensitive scaling relation between the Hall conductivityσ_xyand the longitudinal conductivityσ_xx, namely,σ_xy∝σ_xx^αwith α reaching up to 5, which is exceptionally large compared toα ≤ 2 typical of all solids. The novel Hall responses along with a current-sensitive carrier density and a large Hall angle of 15% point to a giant, current-sensitive Hall effect that is unique to the COC state. Here, we show 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 COC Hall responses.

We extend recent work on hydrodynamics with global multipolarsymmetries — known as “fracton hydrodynamics” — to systems in which themultipolar symmetries are gauged. We refer to the latter as “fractonmagnetohydrodynamics”, in analogy to conventional magnetohydrodynamics(MHD), which governs systems with gauged charge conservation. We showthat fracton MHD arises naturally from higher-rank Maxwell’s equationsand in systems with one-form symmetries obeying certain constraints;while we focus on “minimal” higher-rank generalizations of MHD thatrealize diffusion, our methods may also be used to identify other, moreexotic hydrodynamic theories (e.g., with magnetic subdiffusion). Incontrast to semi-microscopic derivations of MHD, our approach elucidatesthe origin of the hydrodynamic modes by identifying the correspondinghigher-form symmetries. Being rooted in symmetries, the hydrodynamicmodes may persist even when the semi-microscopic equations no longerprovide an accurate description of the system.