Polar and quasicrystal vortex observed in twisted-bilayer molybdenum disulfide

We report the observation of an electric field in twisted-bilayer molybdenum disulfide (MoS ) and elucidate its correlation with local polar domains using four-dimensional scanning transmission electron microscopy (4D-STEM) and first-principles calculations. We reveal the emergence of in-plane topol...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2024-10, Vol.386 (6718), p.198-205
Main Authors: Tsang, Chi Shing, Zheng, Xiaodong, Yang, Tong, Yan, Zhangyuan, Han, Wei, Wong, Lok Wing, Liu, Haijun, Gao, Shan, Leung, Ka Ho, Lee, Chun-Sing, Lau, Shu Ping, Yang, Ming, Zhao, Jiong, Ly, Thuc Hue
Format: Article
Language:English
Subjects:
Electric fields
First principles
Molybdenum
Molybdenum disulfide
Quasicrystals
Scanning transmission electron microscopy
Transmission electron microscopy
Vortices
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Summary:We report the observation of an electric field in twisted-bilayer molybdenum disulfide (MoS ) and elucidate its correlation with local polar domains using four-dimensional scanning transmission electron microscopy (4D-STEM) and first-principles calculations. We reveal the emergence of in-plane topological vortices within the periodic moiré patterns for both commensurate structures at small twist angles and the incommensurate quasicrystal structure that occurs at a 30° twist. The large-angle twist leads to mosaic chiral vortex patterns with tunable characteristics. A twisted quasicrystal bilayer, characterized by its 12-fold rotational symmetry, hosts complex vortex patterns and can be manipulated by picometer-scale interlayer displacement. Our findings highlight that twisting 2D bilayers is a versatile strategy for tailoring local electric polar vortices.
ISSN:0036-8075
1095-9203
1095-9203
DOI:10.1126/science.adp7099