Current-controlled chiral orbital currents in a colossal magnetoresistance material

Colossal magnetoresistance (CMR) is an extraordinary enhancement of the electric conductivity in the presence of a magnetic field. It is conventionally associated with a field-induced spin polarization that drastically reduces spin scattering and electric resistance. Ferrimagnetic Mn₃Si₂Te₆ is an intriguing exception to this rule: it exhibits a 7-order-of-magnitude reduction in ab-plane resistivity that occurs only when a magnetic polarization is avoided [1]. Here we report an exotic quantum state that is driven by ab-plane chiral orbital currents (COC) flowing along edges of MnTe₆ octahedra [2]. The c-axis orbital moments of ab-plane COC couple to the ferrimagnetic Mn spins to drastically increase the ab-plane conductivity (CMR) when an external magnetic field is aligned along the magnetic hard c axis. The COC-driven CMR is thus highly susceptible to external currents. When a small DC current is applied beyond a critical threshold, the coupling of the COC to MnTe₆ octahedra induces a time-dependent, bistable switching that mimics a first-order "melting transition”, which is a hallmark of the COC state. The demonstrated current-control of COC-enabled CMR offers a new paradigm for quantum technologies.