Magnon-exciton proximity coupling at a van der Waals heterointerface

TL;DR

This paper demonstrates a novel hybrid system where magnons in yttrium iron garnet induce a valley Zeeman effect in MoSe2 excitons at their interface, enabling potential microwave-optical information transduction.

Contribution

It reports the first observation of magnon-exciton coupling at a van der Waals heterointerface, combining magnetic and semiconducting 2D materials for hybrid quantum systems.

Findings

Magnons induce a dynamical valley Zeeman effect in MoSe2.

Strong interfacial exchange interactions observed.

Potential for microwave-optical information transduction.

Abstract

Spin and photonic systems are at the heart of modern information devices and emerging quantum technologies. An interplay between electron-hole pairs (excitons) in semiconductors and collective spin excitations (magnons) in magnetic crystals would bridge these heterogeneous systems, leveraging their individual assets in novel interconnected devices. Here, we report the magnon-exciton coupling at the interface between a magnetic thin film and an atomically-thin semiconductor. Our approach allies the long-lived magnons hosted in a film of yttrium iron garnet (YIG) to strongly-bound excitons in a flake of a transition metal dichalcogenide, MoSe$_2$. The magnons induce on the excitons a dynamical valley Zeeman effect ruled by interfacial exchange interactions. This nascent class of hybrid system suggests new opportunities for information transduction between microwave and optical regions.