Control of chiral orbital currents in a colossal magnetoresistance material

TL;DR

This paper uncovers a novel quantum state driven by chiral orbital currents in Mn3Si2Te6, revealing a new mechanism for colossal magnetoresistance that is highly sensitive to small currents and exhibits bistable switching.

Contribution

It introduces an exotic chiral orbital current state that controls CMR and bistable switching, offering a new paradigm for quantum technology applications.

Findings

Chiral orbital currents induce colossal magnetoresistance in Mn3Si2Te6.

The COC state is highly sensitive to small DC currents and exhibits bistable switching.

The COC state couples orbital moments to spins, drastically increasing in-plane conductivity.

Abstract

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, which drastically reduces spin scattering and thus electric resistance. However, ferrimagnetic Mn3Si2Te6 is an intriguing exception to this rule: it exhibits a 7-order-of-magnitude reduction in ab-plane resistivity with a 13-Tesla anisotropy field which occur 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. 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. Both the COC state and its CMR are extraordinarily susceptible to small DC currents exceeding a critical threshold, and a hallmark of this COC state is an exotic time-dependent, bistable switching mimicking a first-order melting transition. The control of the COC-enabled CMR and bistable switching offers a fundamentally new paradigm for quantum technologies.