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arXiv 2401.09010cond-mat.mtrl-scicond-mat.mes-hall
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扭转三层石墨烯准晶体中的鲁棒平带

Robust flat bands in twisted trilayer graphene quasicrystals

Chen-Yue Hao, Zhen Zhan, Pierre A. Pantaleón, Jia-Qi He, Ya-Xin Zhao, Kenji Watanabe, Takashi Taniguchi, Francisco Guinea, Lin He

AI总结:

本文通过直接空间成像和理论计算,证明扭转三层石墨烯准晶体中存在平带,并揭示其局域化对称性随区域变化,为在准周期系统中研究关联物理提供了实验基础。

摘要:

由具有两个独立扭转角的三层石墨烯扭转形成的莫尔结构为研究关联量子现象提供了理想平台,因为理论上预测无限多的角度对会表现出平带。此外,扭转三层石墨烯(TTG)中两个相互不可通约的莫尔图案可以形成高度可调的莫尔准晶体。这使我们能够将周期性莫尔晶体中的关联物理扩展到准周期系统。然而,对莫尔准晶体的结构以及由此产生的平带进行直接的局域表征仍然缺乏,这对于从根本上理解和控制关联莫尔物理至关重要。在这里,我们证明了一系列具有不同扭转角对的TTG中平带的存在,并表明具有不同魔角对的TTG在原子和电子结构上存在显著差异。晶格弛豫和莫尔图案之间的干涉高度依赖于扭转角。我们的直接空间成像在理论计算的支持下,揭示了平带的局域化在莫尔准晶体的不同区域表现出不同的对称性。

英文摘要:

Moiré structures formed by twisting three layers of graphene with two independent twist angles present an ideal platform for studying correlated quantum phenomena, as an infinite set of angle pairs is predicted to exhibit flat bands. Moreover, the two mutually incommensurate moiré patterns among the twisted trilayer graphene (TTG) can form highly tunable moiré quasicrystals. This enables us to extend correlated physics in periodic moiré crystals to quasiperiodic systems. However, direct local characterization of the structure of the moiré quasicrystals and of the resulting flat bands are still lacking, which is crucial to fundamental understanding and control of the correlated moiré physics. Here, we demonstrate the existence of flat bands in a series of TTGs with various twist angle pairs and show that the TTGs with different magic angle pairs are strikingly dissimilar in their atomic and electronic structures. The lattice relaxation and the interference between moiré patterns are highly dependent on the twist angles. Our direct spatial mappings, supported by theoretical calculations, reveal that the localization of the flat bands exhibits distinct symmetries in different regions of the moiré quasicrystals.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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