Experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers

Long Jing Yin, Jia Bin Qiao, Wei Jie Zuo, Wen Tian Li, Lin He

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71 引用 (Scopus)

摘要

Non-Abelian gauge potentials are quite relevant in subatomic physics, but they are relatively rare in a condensed matter context. Here we report the experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers by scanning tunneling microscopy and spectroscopy. At a magic twisted angle, θ≈(1.11±0.05)°, a pronounced sharp peak, which arises from the nondispersive flat bands at the charge neutrality point, is observed in the tunneling density of states due to the action of the non-Abelian gauge fields. Moreover, we observe confined electronic states in the twisted bilayer, as manifested by regularly spaced tunneling peaks with energy spacing δE≈vF/D≈70meV (here vF is the Fermi velocity of graphene and D is the period of the moiré patterns). This indicates that the non-Abelian gauge potentials in twisted graphene bilayers confine low-energy electrons into a triangular array of quantum dots following the modulation of the moiré patterns. Our results also directly demonstrate that the Fermi velocity in twisted bilayers can be tuned from about 106m/s to zero by simply reducing the twisted angle of about 2°.

源语言英语
文章编号081406
期刊Physical Review B - Condensed Matter and Materials Physics
92
8
DOI
出版状态已出版 - 19 8月 2015
已对外发布

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