Realization of fractional-layer transition metal dichalcogenides

作者：Yaxin Zhao, Heng Jin, Zi-Yi Han, Xinlei Zhao, Ya-Ning Ren, Ruohan Zhang, Xiaofeng Zhou, Wenhui Duan, Bing Huang, Yu Zhang, Lin He · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-59007-7 · 被引用次数：10 · 研究领域：2D Materials and Applications、Graphene research and applications、Supramolecular Self-Assembly in Materials

Layered van der Waals transition metal dichalcogenides (TMDCs), generally composed of three atomic X-M-X planes in each layer (M = transition metal, X = chalcogen), provide versatile platforms for exploring diverse quantum phenomena. In each MX2 layer, the M-X bonds are predominantly covalent in nature and, as a result, the cleavage of TMDC crystals normally occurs between the layers. Here we report the controllable realization of fractional-layer WTe2 via an in-situ scanning tunneling microscopy (STM) tip manipulation technique. By applying STM tip pulses, hundreds of the topmost Te atoms are removed to form a nanoscale monolayer Te pit in the 1 T′-WTe2, thus realizing a 2/3-layer WTe2 film. Such a configuration undergoes a spontaneous atomic reconstruction, yielding a unidirectional charge density redistribution with the wavevector and geometry quite distinct from that of pristine 1 T′-WTe2. Our results expand the conventional understanding of the TMDCs and are expected to stimulate further research on the structure and properties of fractional-layer TMDCs. Layers of transition metal dichalcogenides (TMDs) are generally formed by covalently bonded atoms, enabling mechanical exfoliation only in the out-of-plane direction. Here, the authors show the fabrication of fractional 2/3-layers of WTe2 and other TMDs by applying local scanning tunneling microscopy tip pulses and controllably removing the topmost chalcogen atoms.