Emulating spin transport with nonlinear optics, from high-order skyrmions to the topological Hall effect

Aviv Karnieli,Shai Tsesses,Guy Bartal,Ady Arie

doi:10.1038/s41467-021-21250-z

Abstract

Exploring material magnetization led to countless fundamental discoveries and applications, culminating in the field of spintronics. Recently, research effort in this field focused on magnetic skyrmions – topologically robust chiral magnetization textures, capable of storing information and routing spin currents via the topological Hall effect. In this article, we propose an optical system emulating any 2D spin transport phenomena with unprecedented controllability, by employing three-wave mixing in 3D nonlinear photonic crystals. Precise photonic crystal engineering, as well as active all-optical control, enable the realization of effective magnetization textures beyond the limits of thermodynamic stability in current materials. As a proof-of-concept, we theoretically design skyrmionic nonlinear photonic crystals with arbitrary topologies and propose an optical system exhibiting the topological Hall effect. Our work paves the way towards quantum spintronics simulations and novel optoelectronic applications inspired by spintronics, for both classical and quantum optical information processing.

Highlights

Exploring material magnetization led to countless fundamental discoveries and applications, culminating in the field of spintronics
Emulating 2D spin transport necessitates a pseudospin degree of freedom, an effective magnetization field acting on the pseudospin, and a space-time along which the dynamics is probed
We define the pseudospin degree of freedom by considering a nonlinear optical process involving two interacting frequencies, which can be geometrically represented on a Bloch sphere[25,32,44] (Fig. 1a–b)

Summary

Introduction

Exploring material magnetization led to countless fundamental discoveries and applications, culminating in the field of spintronics. Research effort in this field focused on magnetic skyrmions – topologically robust chiral magnetization textures, capable of storing information and routing spin currents via the topological Hall effect. We propose an optical system emulating any 2D spin transport phenomena with unprecedented controllability, by employing three-wave mixing in 3D nonlinear photonic crystals. As well as active all-optical control, enable the realization of effective magnetization textures beyond the limits of thermodynamic stability in current materials. As a proof-of-concept, we theoretically design skyrmionic nonlinear photonic crystals with arbitrary topologies and propose an optical system exhibiting the topological Hall effect. Skyrmions can be applied to control spin transport through the topological Hall effect[11,12,13]: the deflection of a spin-1/2 particle due to its interaction with a topologically nontrivial magnetization. Wherein fabrication capabilities allow a high degree of controllability and straightforward measurement, these experimental analogies created the field of topological photonics[26], enabling many exciting applications, including topologically protected lasing[27,28]

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Results

Conclusion