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arXiv 1805.08232cond-mat.str-el
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Moiré超晶格中的近平Chern带

Nearly Flat Chern Bands in Moiré Superlattices

Ya-Hui Zhang, Dan Mao, Yuan Cao, Pablo Jarillo-Herrero, T. Senthil

摘要:

拓扑和电子相互作用是现代凝聚态物理的两个中心主题。在这里,我们提出了基于石墨烯的系统,其中能带拓扑结构和相互作用效应可以简单地用电场控制。我们研究了一些小扭曲角的扭曲双层系统,其中形成了莫尔超晶格。每个层被选择为AB堆叠的双层石墨烯(BG)、ABC堆叠的三层石墨烯(TG)或六方氮化硼(h-BN)。在这些系统中,垂直施加的电场使得能够控制带宽,并且有趣的是还能够控制陈数。我们发现,与两个微观谷中的每一个相关联的带的陈数可以是$\pm 0,\pm 1,\pm 2, \pm 3$,取决于特定的系统和垂直电场。我们表明,这些石墨烯莫尔超晶格是有前途的平台,实现了一些迷人的多体现象,包括(分数)量子反常霍尔效应。我们还讨论了概念上的相似之处和扭曲双层石墨烯系统建模的影响。

英文摘要:

Topology and electron interactions are two central themes in modern condensed matter physics. Here we propose graphene based systems where both the band topology and interaction effects can be simply controlled with electric fields. We study a number of systems of twisted double layers with small twist angle where a moiré super-lattice is formed. Each layer is chosen to be either AB stacked bilayer graphene (BG), ABC stacked trilayer graphene (TG), or hexagonal boron nitride (h-BN). In these systems a vertical applied electric field enables control of the bandwidth, and interestingly also the Chern number. We find that the Chern numbers of the bands associated with each of the two microscopic valleys can be $\pm 0,\pm 1,\pm 2, \pm 3$ depending on the specific system and vertical electrical field. We show that these graphene moiré super-lattices are promising platforms to realize a number of fascinating many-body phenomena, including (Fractional) Quantum Anomalous Hall Effects. We also discuss conceptual similarities and implications for modeling twisted bilayer graphene systems.

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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