Modeling unconventional spin torques arising from WTe2 as an essential preparation for realizing the proposed THz spin-torque oscillator

Field-free deterministic switching of perpendicular magnetization is essential to achieve high-density and non-volatile magnetic memory, which remains a major challenge because it requires damping-like torques arising from out-of-plane (OOP) spin accumulation. The OOP damping-like torque is also critical to one of the central goals of this MURI project: antiferromagnetic spin-torque oscillator with tunable frequency (studied theoretically by PI-Cheng and PI-Slavin). The collaboration between Singh and PI-Cheng showed for the first time that an OOP damping-like torque arising from the special crystal structure of WTe2 is sufficiently strong to switch a perpendicularly polarized magnet, where magnetic fields are no longer needed. This is a crucial step towards the realization of frequency-tunable antiferromagnetic oscillator using -Fe2O3/ WTe2.

This article has been published in Nature Materials and is available here.