It has been only recently realized that topological vortices associated with structural distortions or ordered spins are rather common in numerous materials where long-range interactions are not dominant. Incommensurate modulations that frequently occur in charge density wave (CDW) materials are often understood in terms of discommensurations with a periodic phase shift. The accumulation of a one-dimensional (1D) phase shift can result in, for example, CDW dislocations in 2H-TaSe₂ with incommensurate CDW (I-CDW). Since any atomic-scale experimental investigation of CDW dislocations in 2H-TaSe₂ has been lacking, we have performed the atomic-scale observation of 2H-TaSe₂ with I-CDW, stabilized with Pd intercalation or strain, with scanning probe microscopy, and unveiled the existence of topological Z₆ or Z₄ vortices with topologically protected 2D winding movements of atomic displacement vectors. The discovery opens the ubiquitous nature of topological vortex domains and a new avenue to explore new facets of various incommensurate modulations or discommensurations.

中文翻译：

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2H-TaSe2不相称电荷密度波中拓扑涡旋的原子尺度观察。

直到最近才意识到，与结构变形或有序自旋相关的拓扑旋涡在许多材料中很普遍，在这些材料中，远距离相互作用并不占优势。电荷密度波（CDW）材料中经常发生的不相称调制通常是根据具有周期性相移的不相称来理解的。一维（1D）相移的累积可能会导致例如2H-TaSe _2中的CDW位错和不相称的CDW（I-CDW）。由于缺乏2H-TaSe ₂中CDW位错的原子级实验研究，因此我们进行了2H-TaSe ₂的原子级观察。用I-CDW，并用Pd插入或应变稳定，并用扫描探针显微镜观察，并揭示了拓扑Z ₆或Z ₄涡旋的存在，该涡旋具有原子位移矢量的拓扑受保护的2D缠绕运动。这一发现打开了拓扑涡旋域的无处不在的性质，并为探索各种不适当的调制或不平衡的新方面开辟了一条新途径。