Visualization of the flat electronic band in twisted bilayer graphene near the magic angle twist

M. Iqbal Bakti Utama, Roland J. Koch, Kyunghoon Lee, Nicolas Leconte, Hongyuan Li, Sihan Zhao, Lili Jiang, Jiayi Zhu, Kenji Watanabe, Takashi Taniguchi, Paul D. Ashby, Alexander Weber-Bargioni, Alex Zettl, Chris Jozwiak, Jeil Jung, Eli Rotenberg, Aaron Bostwick, Feng Wang

Research output: Contribution to journalArticlepeer-review

98 Scopus citations

Abstract

Bilayer graphene has been predicted to host a moiré miniband with flat dispersion if the layers are stacked at specific twist angles known as the ’magic angles’1,2. Recently, twisted bilayer graphene (tBLG) with a magic angle twist was reported to exhibit a correlated insulating state and superconductivity3,4, where the presence of the flat miniband in the system is thought to be essential for the emergence of these ordered phases in the transport measurements. Although tunnelling spectroscopy5–9 and electronic compressibility measurements10 in tBLG have found a van Hove singularity that is consistent with the presence of the flat miniband, a direct observation of the flat dispersion in the momentum space of such a moiré miniband in tBLG is still lacking. Here, we report the visualization of this flat moiré miniband by using angle-resolved photoemission spectroscopy with nanoscale resolution. The high spatial resolution of this technique enabled the measurement of the local electronic structure of the tBLG. The measurements demonstrate the existence of the flat moiré band near the charge neutrality for tBLG close to the magic angle at room temperature.

Original languageEnglish
Pages (from-to)184-188
Number of pages5
JournalNature Physics
Volume17
Issue number2
DOIs
StatePublished - Feb 2021

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