Hidden low-temperature magnetic order revealed through magnetotransport in monolayer CrSBr

TL;DR

This study reveals how magnetotransport in monolayer CrSBr can be electrically and magnetically tuned, showing giant negative and positive magnetoresistance linked to magnetic order and defects, advancing 2D magnetic semiconductor understanding.

Contribution

It demonstrates the electrostatic and magnetic control of magnetotransport in atomically-thin CrSBr, highlighting defect-mediated ferromagnetic coupling and tunable magnetoresistance in 2D magnetic semiconductors.

Findings

Giant negative magnetoresistance from spin-flip scattering in multilayer CrSBr.

Magnetoresistance vanishes below Curie temperature in monolayer CrSBr.

Electrostatic gating tunes defect-mediated ferromagnetic coupling.

Abstract

Magnetic semiconductors are a powerful platform for understanding, utilizing and tuning the interplay between magnetic order and electronic transport. Compared to bulk crystals, two-dimensional magnetic semiconductors have greater tunability, as illustrated by the gate modulation of magnetism in exfoliated CrI$_3$ and Cr$_2$Ge$_2$Te$_6$, but their electrically insulating properties limit their utility in devices. Here we report the simultaneous electrostatic and magnetic control of electronic transport in atomically-thin CrSBr, an A-type antiferromagnetic semiconductor. Through magnetotransport measurements, we find that spin-flip scattering from the interlayer antiferromagnetic configuration of multilayer flakes results in giant negative magnetoresistance. Conversely, magnetoresistance of the ferromagnetic monolayer CrSBr vanishes below the Curie temperature. A second transition ascribed to the ferromagnetic ordering of magnetic defects manifests in a large positive magnetoresistance in the monolayer and a sudden increase of the bulk magnetic susceptibility. We demonstrate this magnetoresistance is tunable with an electrostatic gate, revealing that the ferromagnetic coupling of defects is carrier mediated.