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arXiv · 1504.02519

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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Abstract

The methods for realizing of non-Abelian gauge potentials have been proposed in many different systems in condensed matter1-5. The simplest realization among them may be in a graphene bilayer obtained by slightly relative rotation between the two layers4. Here we report the experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers by scanning tunnelling microscopy and spectroscopy. At a magic twisted angle, theta ~ (1.11+/-0.05)deg, a pronounced sharp peak, which arises from the nondispersive flat bands at the charge neutrality point, are observed in the tunnelling density of states due to the action of the non-Abelian gauge fields4,6-8. Moreover, we observe confined electronic states in the twisted bilayer, as manifested by regularly spaced tunnelling peaks with energy spacing detal E ~ vF/D ~ 70 meV (here vF is the Fermi velocity of graphene and D is the period of the Moire patterns). Our results direct demonstrate 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 Moire patterns.

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Long-Jing Yin, Jia-Bin Qiao, Wei-Jie Zuo, Wen-Tian Li, Lin He. 2015-04-09. Experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers. https://doi.org/10.1103/physrevb.92.081406

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