Swapping Exchange and Spin-Orbit Coupling in 2D van der Waals Heterostructures

TL;DR

This paper proposes a method to swap exchange and spin-orbit interactions in 2D van der Waals heterostructures using gate-controlled multilayer devices, enabling new functionalities in 2D spintronics.

Contribution

It introduces a novel concept of swapping spin interactions in 2D heterostructures through ab initio simulations and gate tuning, demonstrating bifunctional device potential.

Findings

Successful swapping of exchange and spin-orbit interactions in simulations

Gate-dependent layer polarization enables control of spin interactions

Potential for designing multifunctional 2D spintronic devices

Abstract

The concept of swapping the two most important spin interactions -- exchange and spin-orbit coupling -- is proposed based on two-dimensional multilayer van der Waals heterostructures. Specifically, we show by performing realistic ab initio simulations, that a single device consisting of a bilayer graphene sandwiched by a 2D ferromagnet Cr$_2$Ge$_2$Te$_6$ (CGT) and a monolayer WS$_2$, is able not only to generate, but also to swap the two interactions. The highly efficient swapping is enabled by the interplay of gate-dependent layer polarization in bilayer graphene and short-range spin-orbit and exchange proximity effects affecting only the layers in contact with the sandwiching materials. We call these structures ex-so-tic, for supplying either exchange (ex) or spin-orbit (so) coupling in a single device, by gating. Such bifunctional devices demonstrate the potential of van der Waals spintronics engineering using 2D crystal multilayers.