Optical control of topological memory based on orbital magnetization

TL;DR

This paper explores how circularly polarized light interacts with Chern insulators, proposing a method to switch topological memory and create domain walls with protected edge modes using optical control.

Contribution

It introduces a novel optical protocol to manipulate topological memory in Chern insulators via circularly polarized light, leveraging Berry curvature interactions.

Findings

Interaction energy couples to light helicity via Berry curvature

Proposed experimental protocol for optical switching of topological memory

Laser beams can nucleate domains with opposite magnetization and chiral edge modes

Abstract

Under suitable conditions, some twisted graphene multilayers and transition-metal dichalcogenides become Chern insulators, exhibiting the anomalous quantum Hall effect and orbital magnetization due to spontaneous valley polarization. We study interaction of a Chern insulator with circularly polarized light. The interaction energy contains an antisymmetric term that couples to the helicity of incident light. For a two-band Chern insulator, this term is expressed as an integral involving the Berry curvature of the system. Taking advantage of this interaction, we propose an experimental protocol for switching topological memory based on orbital magnetization by circularly polarized light. Moreover, two laser beams of opposite circular polarization can nucleate domains of opposite magnetization and thus produce an optically configurable domain wall carrying topologically protected chiral edge modes.