Field-Free Spin-Orbit Torque Switching in Janus Chromium Dichalcogenides

Nano Lett. 2024 Sep 25;24(38):11889-11894. doi: 10.1021/acs.nanolett.4c03029. Epub 2024 Sep 13.

Abstract

We predict a very large spin-orbit torque (SOT) capability of magnetic chromium-based transition-metal dichalcogenide (TMD) monolayers 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 ∼100 V nm-1 in non-Janus CrTe2, completely out of experimental reach. By performing transport simulations on carefully derived Wannier tight-binding models, Janus systems are found to exhibit an SOT performance comparable to the most efficient two-dimensional materials, while additionally allowing for field-free perpendicular magnetization switching, due to their reduced in-plane symmetry. Altogether, our findings evidence that magnetic Janus TMDs stand as suitable candidates for ultimate SOT-MRAM devices in an ultracompact self-induced SOT scheme.

Keywords: 2D materials; spin−orbit torque; transition metal dichalcogenide; van der Waals ferromagnet.