Spin-orbit torque (SOT) driven deterministic control of the magnetization state of a magnet with perpendicular magnetic anisotropy (PMA) is key to next generation spintronic applications including non-volatile, ultrafast, and energy efficient data storage devices. But, field-free deterministic switching of perpendicular magnetization remains a challenge because it requires an out-of-plane anti-damping torque, which is not allowed in conventional spin source materials such as heavy metals (HM) and topological insulators due to the system's symmetry. The exploitation of low-crystal symmetries in emergent quantum materials offers a unique approach to achieve SOTs with unconventional forms. Here, we report the first experimental realization of field-free deterministic magnetic switching of a perpendicularly polarized van der Waals (vdW) magnet employing an out-of-plane anti-damping SOT generated in layered WTe2 which is a low-crystal symmetry quantum material. The numerical simulations confirm that out-of-plane antidamping torque in WTe2 is responsible for the observed magnetization switching in the perpendicular direction.
@article{arxiv.2012.12388,
title = {Field-free deterministic switching of a perpendicularly polarized magnet using unconventional spin-orbit torques in WTe2},
author = {I-Hsuan Kao and Ryan Muzzio and Hantao Zhang and Menglin Zhu and Jacob Gobbo and Daniel Weber and Rahul Rao and Jiahan Li and James H. Edgar and Joshua E. Goldberger and Jiaqiang Yan and David G. Mandrus and Jinwoo Hwang and Ran Cheng and Jyoti Katoch and Simranjeet Singh},
journal= {arXiv preprint arXiv:2012.12388},
year = {2020}
}