Polar and quasicrystal vortex observed in twisted-bilayer molybdenum disulfide
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
) 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.