Sun Zeyuan, Hong Canyu, Chen Yi, Sheng Zhiyuan, Wu Shuang, Wang Zhanshan, Liang Bokai, Liu Wei-Tao, Yuan Zhe, Wu Yizheng, Mi Qixi, Liu Zhongkai, Shen Jian, Wu Shiwei
State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (MOE), and Department of Physics, Fudan University, Shanghai, China.
School of Physical Science and Technology, ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai, China.
Nat Mater. 2025 Feb;24(2):226-233. doi: 10.1038/s41563-024-02074-w. Epub 2025 Jan 13.
Polymorphism, commonly denoting diverse molecular or crystal structures, is crucial in the natural sciences. In van der Waals antiferromagnets, a new type of magnetic polymorphism arises, presenting multiple layer-selective magnetic structures with identical total magnetization. However, resolving and manipulating such magnetic polymorphs remain challenging. Here, phase-resolved magnetic second harmonic generation microscopy is used to elucidate magnetic polymorphism in 2D layered antiferromagnet CrSBr, demonstrating deterministic and layer-selective switching of magnetic polymorphs. Using a nonlinear magneto-optical technique, we unambiguously resolve the polymorphic spin-flip transitions in CrSBr bilayers and tetralayers through both the amplitude and phase of light. Remarkably, the deterministic routing of polymorphic spin-flip transitions originates from a 'layer-sharing' effect, where the transitions are governed by laterally extended layers acting as 'control bits'. We envision that such controllable magnetic polymorphism could be ubiquitous for van der Waals layered antiferromagnets, enabling new designs and constructions of spintronic and opto-spintronic devices for probabilistic computation and neuromorphic engineering.
多态性通常指多样的分子或晶体结构，在自然科学中至关重要。在范德华反铁磁体中，出现了一种新型磁多态性，呈现出具有相同总磁化强度的多种层选择性磁结构。然而，解析和操控这种磁多态性仍然具有挑战性。在此，利用相分辨磁二次谐波产生显微镜来阐明二维层状反铁磁体CrSBr中的磁多态性，展示了磁多态性的确定性和层选择性切换。使用非线性磁光技术，我们通过光的振幅和相位明确解析了CrSBr双层和四层中的多态性自旋翻转跃迁。值得注意的是，多态性自旋翻转跃迁的确定性路径源于一种“层共享”效应，其中跃迁由作为“控制位”的横向扩展层控制。我们设想，这种可控磁多态性可能在范德华层状反铁磁体中普遍存在，为概率计算和神经形态工程的自旋电子器件和光自旋电子器件带来新的设计和构建。
