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arXiv · 2110.10823

Electronic confinement in quantum dots of twisted bilayer graphene

Xiao-Feng Zhou·Yi-Wen Liu·Hong-Yi Yan·Zhong-Qiu Fu·Haiwen Liu·Lin He
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Abstract

Electronic properties of quantum dots (QDs) depend sensitively on their parent materials. Therefore, confined electronic states in graphene QDs (GQDs) of monolayer and Bernal-stacked bilayer graphene are quite different. Twisted bilayer graphene (TBG) is distinct from monolayer and Bernal-stacked bilayer graphene because of the new degree of freedom: twist angle. In the past few years, numerous efforts have been made to realize the GQDs of monolayer and Bernal-stacked bilayer graphene and achieved great success. Thus far, however, strategies for realizing GQDs of TBG have been elusive. Here, we demonstrate a general approach for fabricating stationary GQDs of TBG by introducing nanoscale p-n junctions with sharp boundaries in the TBG. We verify the confinement of low-energy massless Dirac fermions via whispering-gallery modes in the GQDs of TBG. Unexpectedly, electronic states around van Hove singularities of the TBG are also strongly modified around the GQDs. Such a feature has never been reported and is attributed to spatial variation of the interlayer coupling in the TBG induced by the GQDs.

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Xiao-Feng Zhou, Yi-Wen Liu, Hong-Yi Yan, Zhong-Qiu Fu, Haiwen Liu, Lin He. 2021-10-20. Electronic confinement in quantum dots of twisted bilayer graphene. https://doi.org/10.1103/physrevb.104.235417

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