  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 sigma_xy and the longitudinal
conductivity sigma_xx, namely, sigma_xy ~ sigma_xx^alpha with alpha ranging
between 3 and 5, which is both sensitive to external current and exceptionally
large compared to alpha < 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 is
unique, as it is generated and controlled via the interaction between intrinsic
COC and applied external currents, which leads to novel transport phenomena of
fundamental and technological significance and requires new physics for
explanation.
