Magnetically Switchable Light-Matter Interaction in the Two-Dimensional Magnet CrI3

TL;DR

This paper introduces a magnetic photogalvanic effect in the 2D magnetic insulator CrI3, demonstrating a record photoconductivity response that can be controlled via magnetic phase transitions, opening new avenues for photovoltaic and optoelectronic applications.

Contribution

It proposes a novel magnetic light-matter interaction mechanism in CrI3 that does not require static polarization and demonstrates its potential for device applications.

Findings

Record photoconductivity response (>200 μA V^{-2}) in CrI3 under visible light.

Reversible current switching through magnetic phase transitions.

Identification of a new light-matter interaction mechanism linked to magnetic properties.

Abstract

Coupling different physical properties is a fascinating subject of physics. Already well-known are the multiferroics which show properties of ferroelectrics and magnets. But ferroelectricity by itself also entails the bulk photovoltaic effect, a light-matter interaction which generates dc currents. Here we propose a magnetic photogalvanic effect that couples the magnetism to the light-matter interaction. This phenomenon emerges from the $\mathbf{k}$ to $\mathbf{-k}$ symmetry-breaking in the band structure and does not require a static polarization. It is distinct from other known bulk photovoltaic mechanisms such as the shift current. We demonstrate such phenomena in a newly discovered layered magnetic insulator CrI$_3$. A record photoconductivity response (more than 200 $\mu A V^{-2} $) is generated under the irradiation of a visible light in the antiferromagnetic phase. The current can be reversed and switched by controllable magnetic phase transitions. Our work paves a new route for photovoltaic and optoelectronic devices and provides a sensitive probe for the magnetic transition.