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arXiv · 2311.07819

Imaging Self-aligned Moir\'e Crystals and Quasicrystals in Magic-angle Bilayer Graphene on hBN Heterostructures

Xinyuan Lai·Daniele Guerci·Guohong Li·Kenji Watanabe·Takashi Taniguchi·Justin Wilson·Jedediah H. Pixley·Eva Y. Andrei
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Abstract

Using scanning-tunneling-microscopy and theoretical modeling on heterostructures of twisted bilayer graphene and hexagonal Boron-Nitride, we show that the emergent super-moire structures display a rich landscape of moire-crystals and quasicrystals. We reveal a phase-diagram comprised of commensurate moire-crystals embedded in swaths of moire quasicrystals. The 1:1 commensurate crystal, expected to be a Chern insulator, should only exist at one point on the phase-diagram, implying that it ought to be practically undetectable. Surprisingly we find that the commensurate crystals exist over a much wider than predicted range, providing evidence of an unexpected self-alignment mechanism that is explained using an elastic-network model. The remainder of the phase-diagram, where we observe tunable quasicrystals, affords a new platform for exploring the unique electronic-properties of these rarely found in nature structures.

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Xinyuan Lai, Daniele Guerci, Guohong Li, Kenji Watanabe, Takashi Taniguchi, Justin Wilson, Jedediah H. Pixley, Eva Y. Andrei. 2023-11-14. Imaging Self-aligned Moir\'e Crystals and Quasicrystals in Magic-angle Bilayer Graphene on hBN Heterostructures. https://arxiv.org/abs/2311.07819

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