Spin-orbit Torque Switching in an All-Van der Waals Heterostructure

TL;DR

This paper demonstrates that van der Waals heterostructures combining WTe2 and Fe3GeTe2 enable efficient spin-orbit torque switching with low current density, promising for energy-efficient spintronic devices.

Contribution

It introduces an all-vdW heterostructure with atomically sharp interfaces that achieves high SOT efficiency and low switching current, advancing spintronic device engineering.

Findings

WTe2 exhibits high SOT efficiency (~4.6) and conductivity (~2.25×10^5 Ω^{-1}m^{-1}].

Achieved switching current density of 3.90×10^6 A/cm^2 at 150 K, much lower than conventional materials.

All-vdW heterostructure enhances energy efficiency in magnetization control.

Abstract

Current-induced control of magnetization in ferromagnets using spin-orbit torque (SOT) has drawn attention as a new mechanism for fast and energy efficient magnetic memory devices. Energy-efficient spintronic devices require a spin-current source with a large SOT efficiency (${\xi}$) and electrical conductivity (${\sigma}$), and an efficient spin injection across a transparent interface. Herein, we use single crystals of the van der Waals (vdW) topological semimetal WTe$_2$ and vdW ferromagnet Fe$_3$GeTe$_2$ to satisfy the requirements in their all-vdW-heterostructure with an atomically sharp interface. The results exhibit values of ${\xi}{\approx}4.6$ and ${\sigma}{\approx}2.25{\times}10^5 {\Omega}^{-1} m^{-1}$ for WTe$_2$. Moreover, we obtain the significantly reduced switching current density of $3.90{\times}10^6 A/cm^2$ at 150 K, which is an order of magnitude smaller than those of conventional heavy-metal/ ferromagnet thin films. These findings highlight that engineering vdW-type topological materials and magnets offers a promising route to energy-efficient magnetization control in SOT-based spintronics.