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arXiv · 2112.11620

Direct Imaging Strain-field Vortex Networks in Twisted Bilayer Graphene Magnified by Moir\'e Superlattices

Ya-Ning Ren·Yi-Wen Liu·Chao Yan·Lin He
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Abstract

In two-dimensional (2D) twisted bilayers, the van der Waals (vdW) interlayer interaction introduces atomic-scale reconstruction at interface by locally rotating lattice to form strain-field vortex networks in their moir\'e superlattice. However, direct imaging the tiny local lattice rotation of the strain-field vortex requires extremely high spatial resolution and is an outstanding challenge in experiment. Here, a topmost small-period graphene moir\'e pattern is introduced to magnify sub-Angstrom distortions of the lattice and tiny local lattice rotation in underlying twisted bilayer graphene (TBG). The local periods and low-energy van Hove singularities of the topmost graphene moir\'e patterns are spatially modified by the atomic-scale reconstruction of the underlying TBG, thus enabling real-space imaging of the strain-field vortex networks. Our results indicate that structure-reconstructed vdW systems can provide a unique substrate to spatially engineer supported two-dimensional materials both in structures and electronic properties.

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Ya-Ning Ren, Yi-Wen Liu, Chao Yan, Lin He. 2021-12-22. Direct Imaging Strain-field Vortex Networks in Twisted Bilayer Graphene Magnified by Moir\'e Superlattices. https://arxiv.org/abs/2112.11620

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