Giant Spin-Orbit Torque in Cr-based Janus Transition Metal Dichalcogenides

TL;DR

This paper demonstrates that Janus chromium-based transition metal dichalcogenides exhibit giant spin-orbit torque due to structural inversion symmetry breaking, making them promising for efficient, field-free magnetic memory devices.

Contribution

It reveals the large SOT response in Janus CrXTe TMDs caused by Rashba splitting, with potential for field-free magnetization switching, advancing 2D spintronic applications.

Findings

Janus CrXTe TMDs show giant SOT response.

SOT performance comparable to top 2D materials.

Enables field-free perpendicular magnetization switching.

Abstract

We report a very large spin-orbit torque (SOT) capability of chromium-based transition metal dichalcogenides (TMD) in their Janus forms CrXTe, with X=S,Se. The structural inversion symmetry breaking, inherent to Janus structures is responsible for a large SOT response generated by giant Rashba splitting, equivalent to that obtained by applying a transverse electric field of $\sim 100 \,\text{V} \,\text{nm}^{-1}$ in non-Janus CrTe\textsubscript{2}, completely out of experimental reach. By performing transport simulations on custom-made Wannier tight-binding models, Janus systems are found to exhibit a SOT performance comparable to the most efficient two-dimensional materials, while allowing for field-free perpendicular magnetization switching owing to their reduced in-plane symmetry. Altogether, our findings evidence that magnetic Janus TMDs stand as suitable candidates for ultimate SOT-MRAM devices.