Published on Science (11 October 2024)
Author(s): Chi Shing Tsang, Xiaodong Zheng, Tong Yang, Zhangyuan Yan, Wei Han, Lok Wing Wong, Haijun Liu, Shan Gao, Ka Ho Leung, Chun-Sing Lee, Shu Ping Lau, Ming Yang, Jiong Zhao, Thuc Hue Ly
Abstract
We report the observation of an electric field in twisted-bilayer molybdenum disulfide (MoS2) 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.
Read more: https://www.science.org/doi/10.1126/science.adp7099