Observation of Coexisting Dirac Bands and Moiré Flat Bands in Magic-Angle Twisted Trilayer Graphene

Yiwei Li; Shihao Zhang; Fanqiang Chen; Liyang Wei; Zonglin Zhang; Hanbo Xiao; Han Gao; Moyu Chen; Shijun Liang; Ding Pei; Lixuan Xu; Kenji Watanabe; Takashi Taniguchi; Lexian Yang; Feng Miao; Jianpeng Liu; Bin Cheng; Meixiao Wang; Yulin Chen; Zhongkai Liu

doi:10.1002/adma.202205996

Observation of Coexisting Dirac Bands and Moiré Flat Bands in Magic-Angle Twisted Trilayer Graphene

Adv Mater. 2022 Oct;34(42):e2205996. doi: 10.1002/adma.202205996. Epub 2022 Sep 16.

Authors

Yiwei Li^{1

2}, Shihao Zhang^{1

3}, Fanqiang Chen⁴, Liyang Wei¹, Zonglin Zhang¹, Hanbo Xiao¹, Han Gao¹, Moyu Chen⁴, Shijun Liang⁴, Ding Pei^{1

3}, Lixuan Xu⁵, Kenji Watanabe⁶, Takashi Taniguchi⁷, Lexian Yang^{5

8}, Feng Miao⁴, Jianpeng Liu^{1

3}, Bin Cheng⁹, Meixiao Wang^{1

3}, Yulin Chen^{1

3

5

10}, Zhongkai Liu^{1

3}

Affiliations

¹ School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China.
² Institute for Advanced Studies, Wuhan University, Luojiashan Street, Wuhan, Hubei, 430072, P. R. China.
³ ShanghaiTech Laboratory for Topological Physics, Shanghai, 200031, P. R. China.
⁴ National Laboratory of Solid State Microstructures, School of Physics, Institute of Brain-Inspired Intelligence, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
⁵ State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, P. R. China.
⁶ Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
⁷ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
⁸ Frontier Science Center for Quantum Information, Beijing, 100084, P. R. China.
⁹ Institute of Interdisciplinary Physical Sciences, School of Science, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China.
¹⁰ Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK.

PMID: 36043946
DOI: 10.1002/adma.202205996

Abstract

Moiré superlattices that consist of two or more layers of 2D materials stacked together with a small twist angle have emerged as a tunable platform to realize various correlated and topological phases, such as Mott insulators, unconventional superconductivity, and quantum anomalous Hall effect. Recently, magic-angle twisted trilayer graphene (MATTG) has shown both robust superconductivity similar to magic-angle twisted bilayer graphene and other unique properties, including the Pauli-limit violating and re-entrant superconductivity. These rich properties are deeply rooted in its electronic structure under the influence of distinct moiré potential and mirror symmetry. Here, combining nanometer-scale spatially resolved angle-resolved photoemission spectroscopy and scanning tunneling microscopy/spectroscopy, the as-yet unexplored band structure of MATTG near charge neutrality is systematically measured. These measurements reveal the coexistence of the distinct dispersive Dirac band with the emergent moiré flat band, showing nice agreement with the theoretical calculations. These results serve as a stepstone for further understanding of the unconventional superconductivity in MATTG.

Keywords: Dirac fermions; flat bands; magic-angle twisted trilayer graphene; moiré patterns.

Abstract

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