Chen Chia-Ju, Drevelow Tim, Lin Yu-Tung, Chen Yi-Pin, Cheng Tzu-Yen, Lin Yen-Hui, Heinze Stefan, Hsu Pin-Jui
Department of Physics, National Tsing Hua University, Hsinchu, Taiwan.
Institute of Theoretical Physics and Astrophysics, University of Kiel, Kiel, Germany.
Nat Commun. 2025 Aug 11;16(1):7423. doi: 10.1038/s41467-025-62465-8.
Crystalline strain is typically considered as an effective approach to engineer low-dimensional antiferromagnets. However, a direct visualization of strained-tailored noncollinear spin textures in antiferromagnetic atomic layers has so far not been achieved. Here, we uncover a strain-induced transition from a three-dimensional noncollinear spin state in pseudomorphic Mn bilayer to a cycloidal spin spiral with a canted rotation plane in reconstructed Mn bilayer on the Ag(111) surface. These spin states are spatially imaged on the atomic scale by spin-polarized scanning tunneling microscopy revealing the correlation of atomic and magnetic structures. As demonstrated via first-principles electronic structure theory, the three-dimensional noncollinear spin state arises from the superposition of spin spiral and antiferromagnetic order due to higher-order exchange interactions. In reconstructed Mn bilayer, by contrast, the antiferromagnetic order is hindered by interlayer exchange coupling resulting in a pure spin spiral state. Our work highlights the complex interplay of atomic structure, intra- and interlayer exchange, as well as higher-order exchange interactions at antiferromagnetically coupled interfaces.
晶体应变通常被认为是设计低维反铁磁体的有效方法。然而，迄今为止，尚未实现对反铁磁原子层中应变定制的非共线自旋纹理的直接可视化。在这里，我们揭示了一种应变诱导的转变，从赝晶态锰双层中的三维非共线自旋态转变为在Ag(111)表面重构锰双层中具有倾斜旋转平面的摆线自旋螺旋。这些自旋态通过自旋极化扫描隧道显微镜在原子尺度上进行空间成像，揭示了原子结构与磁结构的相关性。通过第一性原理电子结构理论证明，由于高阶交换相互作用，三维非共线自旋态源于自旋螺旋和反铁磁序的叠加。相比之下，在重构锰双层中，反铁磁序受到层间交换耦合的阻碍，导致纯自旋螺旋态。我们的工作突出了原子结构、层内和层间交换以及反铁磁耦合界面处高阶交换相互作用之间的复杂相互作用。
