Recent progress on controlling spin-orbit torques by materials design

Spin-orbit torques (SOTs) provide an energy-efficient approach for the electrical manipulation of magnetization, pivotal for next-generation information storage and processing devices. SOTs can be generated via various mechanisms, such as spin Hall effect, Rashba-Edelstein effect, orbital Hall effect, magnons, and spin swapping. SOTs-based devices hold potential advantages over spin-transfer torque (STT) devices, including low power consumption, enhanced durability, and a broader selection of applicable materials for both SOT generation and excitation. Despite the discovery of numerous materials capable of generating significant SOTs, achieving efficient and deterministic field-free switching of perpendicular magnetization remains a critical challenge, which is essential for the practical deployment of SOT in high-density magnetic memories. This review highlights recent progress in controlling SOTs through innovative materials design, encompassing strategies such as strain engineering of the spin Hall angle, interfacial engineering of the spin transmissivity and topological surface states, and symmetry engineering to achieve deterministic field-free switching of perpendicular magnetization. By exploring these effective methods for manipulating SOTs, this review aims to lay the groundwork for the development of optimized spintronics devices and applications.