量子材料中的自旋—动量锁定新效应

继铁磁金属之后，具有强自旋轨道耦合与空间反演破缺的自旋极化量子材料，通过自旋—动量锁定（如Rashba、Dresselhaus自旋劈裂），实现了如自旋轨道矩、自旋场效应晶体管等新一代自旋电子学效应。近期，通过耦合新自由度，研究者们发现了一些新奇的自旋—动量锁定效应，包括突破空间反演对称限制的“隐藏自旋极化”效应和突破自旋轨道耦合限制的“反铁磁自旋极化”效应，这些发现再一次拓宽了可利用的自旋电子学材料。文章简要回顾了自旋—动量锁定效应的基本原理和发展现状，重点介绍了耦合实空间自由度的自旋—动量—层锁定效应，即隐藏自旋极化；和耦合局域磁矩自由度产生的与自旋轨道耦合无关的自旋—动量锁定效应，即反铁磁自旋极化；以及与两者相关的新型自旋电子学效应。最后，展望了自旋—动量锁定中多自由度耦合问题、隐藏X物理和反铁磁自旋电子学三个方面的未来发展。

Spin-momentum locking and its derivative effects in quantum materials

Spin-polarized quantum materials exhibiting strong spin-orbital coupling (SOC) and space inversion breaking have led to novel spintronic effects, such as spin-orbital torque and spin field effect transistors, through the mechanism of spin-momentum locking (e. g. Rashba and Dresselhaus spin-splitting). Recently, researchers have made significant discoveries regarding spin-momentum locking effects by introducing additional degrees of freedom. These include the hidden spin polarization effect and the antiferromagnetic spin splitting effect, which break the limit of inversion symmetry and the constraint of SOC, respectively. These findings extend the scope of available spintronic materials. We first offer a concise overview of the fundamental principles and current developments in spin-momentum locking. Next, we focus on the hidden spin polarization as a spin-momentum-layer locking effect, and antiferromagnetic spin splitting without the assistance of spin-orbit coupling. We also discuss emerging spintronic effects associated with these phenomena. Lastly, we provide insights into the future progress of multi-degree-of-freedom coupling in spin-momentum locking, and also potential applications for the next generation of spin-polarized materials.