Deng Ying, Li Zefang, Li Guanqi, Shen Xi, Zhang Huai, Wang Junlin, Wu Lijun, Guo Jiangteng, Hu Yue, Hu Xuange, Liu Can, Qin Minghui, Yu Richeng, Gao Xingsen, Liao Zhimin, Liu Junming, Ma Xiang, Yu Dapeng, Xiang Bin, Hou Zhipeng, Zhu Yimei, Fu Xuewen
Ultrafast Electron Microscopy Laboratory, The MOE Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics, Nankai University, Tianjin 300071, China.
School of Integrated Circuits, Guangdong University of Technology, Guangzhou 510006, China.
ACS Nano. 2025 Sep 16;19(36):32721-32731. doi: 10.1021/acsnano.5c10466. Epub 2025 Sep 4.
Superlattices (SLs) based on two-dimensional (2D) van der Waals (vdW) materials, abbreviated as 2D-SLs, have garnered significant attention due to their customizable properties. 2D-SLs can be engineered by mechanical stacking or chemical intercalation to achieve diverse forms of symmetry breaking, resulting in exotic phenomena like the quantum anomalous Hall effect and topological magnetism. Hitherto, broken symmetries in 2D-SLs have been widely produced within lateral planes or three dimensions. However, symmetry breaking along the vertical direction, specifically as an out-of-plane one-dimensional (1D) polarized superlattice, has not yet been achieved. Here, we report a so far unseen out-of-plane 1D polarized vdW ferromagnetic superlattice achieved through an approach of two-step intercalation and de-embedding of chromium (Cr)-based 2D vdW magnets. The off-centering polarization of both intrinsic and intercalated Cr atoms in this (1 × 1 × 2) superstructure breaks the mirror symmetry vertically, yielding a Dzyaloshinskii-Moriya interaction (DMI). This results in high-density Néel-type magnetic skyrmions over a broad temperature range. Notably, sub-100 nm Néel-type skyrmions at room temperature (RT) can be achieved by tuning the Cr intercalation ratio, marking the first binary compound RT Néel-type skyrmionic vdW magnet. Our work expands the 2D-SL family with a class of out-of-plane 1D polarized ferromagnetic superlattice with tunable topological magnetism.
基于二维（2D）范德华（vdW）材料的超晶格（SLs），简称为2D-SLs，因其可定制的特性而备受关注。2D-SLs可以通过机械堆叠或化学插层来设计，以实现多种形式的对称性破缺，从而产生诸如量子反常霍尔效应和拓扑磁性等奇异现象。迄今为止，2D-SLs中的对称性破缺已在横向平面或三维空间中广泛产生。然而，沿垂直方向的对称性破缺，特别是作为面外一维（1D）极化超晶格，尚未实现。在此，我们报告了一种迄今未见的面外1D极化vdW铁磁超晶格，它是通过基于铬（Cr）的2D vdW磁体的两步插层和去嵌入方法实现的。在这种（1×1×2）超结构中，本征和插层Cr原子的偏心极化打破了垂直方向的镜面对称性，产生了Dzyaloshinskii-Moriya相互作用（DMI）。这导致在很宽的温度范围内出现高密度的尼尔型磁斯格明子。值得注意的是，通过调整Cr插层比例，可以在室温（RT）下实现亚100 nm的尼尔型斯格明子，这标志着首个二元化合物室温尼尔型斯格明子vdW磁体。我们的工作通过一类具有可调拓扑磁性的面外1D极化铁磁超晶格扩展了2D-SL家族。
