Current-induced spin-orbit torque (SOT) plays a crucial role in the next-generation spin-orbitronics. Enhancing its efficiency is both fundamentally and practically interesting and remains a challenge to date. Recently, orbital counterparts of spin effects that do not rely on the spin-orbit coupling (SOC) have been found as an alternative mechanism to realize it. This work highlights the engineering of copper oxidation states for manipulating the orbital current and its torque in the CuOx-based heterostructures. The orbital hybridization and thus the orbital-Rashba-Edelstein effect at the CuOx/Cu interfaces are significantly enhanced by increasing the copper oxidation state, yielding a torque efficiency that is almost ten times larger than the conventional heavy metals. The Cu4O3/Cu interface, rather than the widely accepted CuO/Cu interface, is revealed to account for the enhanced SOT performance in the CuOx-based heterostructures. In addition, the torque efficiency can be alternatively switched between high and low thresholds through the redox reaction. The current results establish an exotic and robust strategy for engineering the orbital current and SOT for spin-orbitronics, which applies to other weak-SOC materials.
@article{arxiv.2601.12841,
title = {Engineering of Orbital Hybridization: An Exotic Strategy to Manipulate Orbital Current},
author = {Kun Zheng and Haonan Wang and Ju Chen and Hongxin Cui and Jing Meng and Zheng Li and Cuimei Cao and Haoyu Lin and Yuhao Wang and Keqi Xia and Jiahao Liu and Xiaoyu Feng and Hui Zhang and Bocheng Yu and Jiyuan Li and Yang Xu and Zhengzhong Yang and Shijing Gong and Qingfeng Zhan and Tian Shang},
journal= {arXiv preprint arXiv:2601.12841},
year = {2026}
}