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Fermi Velocity Reduction of Dirac Fermions around the Brillouin Zone Center in In 2 Se 3 –Bilayer Graphene Heterostructures
Author(s) -
Wang Zhenyu,
Hao Zhanyang,
Yu Yayun,
Wang Yuan,
Kumar Shiv,
Xie Xiangnan,
Tong Mingyu,
Deng Ke,
Hao YuJie,
Ma XiaoMing,
Zhang Ke,
Liu Cai,
Ma Mingxiang,
Mei Jiawei,
Wang Guang,
Schwier Eike F.,
Shimada Kenya,
Xu Fufang,
Liu Chang,
Huang Wen,
Wang Jianfeng,
Jiang Tian,
Chen Chaoyu
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202007503
Subject(s) - brillouin zone , condensed matter physics , graphene , dirac fermion , superlattice , bilayer graphene , fermi level , physics , fermi energy , dirac (video compression format) , angle resolved photoemission spectroscopy , heterojunction , materials science , electronic structure , quantum mechanics , electron , neutrino
Emergent phenomena such as unconventional superconductivity, Mott‐like insulators, and the peculiar quantum Hall effect in graphene‐based heterostructures are proposed to stem from the superlattice‐induced renormalization of (moiré) Dirac fermions at the graphene Brillouin zone corners. Understanding the corresponding band structure commonly demands photoemission spectroscopy with both sub‐meV resolution and large‐momentum coverage, beyond the capability of the current state‐of‐the‐art. Here the realization of moiré Dirac cones around the Brillouin zone center in monolayer In 2 Se 3 /bilayer graphene heterostructure is reported. The renormalization is evidenced by reduced Fermi velocity ( ≈ 23%) of the moiré Dirac cones and the reshaped Dirac point at the Γ point where they intersect. While there have been many theoretical predictions and much indirect experimental evidence, the findings here are the first direct observation of Fermi velocity reduction of the moiré Dirac cones. These features suggest strong In 2 Se 3 /graphene interlayer coupling, which is comparable with that in twisted bilayer graphene. The strategy expands the choice of materials in the heterostructure design and stimulates subsequent broad investigations of emergent physics at the sub‐meV energy scale.