Evolution of flat band and role of lattice relaxations in twisted bilayer graphene

Fuente: arXiv
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Hauptverfasser: Li, Qian, Zhang, Hongyun, Wang, Yijie, Chen, Wanying, Bao, Changhua, Liu, Qinxin, Lin, Tianyun, Zhang, Shuai, Zhang, Haoxiong, Watanabe, Kenji, Taniguchi, Takashi, Avila, Jose, Dudin, Pavel, Li, Qunyang, Yu, Pu, Duan, Wenhui, Song, Zhida, Zhou, Shuyun
Format: Preprint
Veröffentlicht: 2024
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author Li, Qian
Zhang, Hongyun
Wang, Yijie
Chen, Wanying
Bao, Changhua
Liu, Qinxin
Lin, Tianyun
Zhang, Shuai
Zhang, Haoxiong
Watanabe, Kenji
Taniguchi, Takashi
Avila, Jose
Dudin, Pavel
Li, Qunyang
Yu, Pu
Duan, Wenhui
Song, Zhida
Zhou, Shuyun
author_facet Li, Qian
Zhang, Hongyun
Wang, Yijie
Chen, Wanying
Bao, Changhua
Liu, Qinxin
Lin, Tianyun
Zhang, Shuai
Zhang, Haoxiong
Watanabe, Kenji
Taniguchi, Takashi
Avila, Jose
Dudin, Pavel
Li, Qunyang
Yu, Pu
Duan, Wenhui
Song, Zhida
Zhou, Shuyun
contents Magic-angle twisted bilayer graphene (MATBG) exhibits correlated phenomena such as superconductivity and Mott insulating state related to the weakly dispersing flat band near the Fermi energy. Beyond its moiré period, such flat band is expected to be sensitive to lattice relaxations. Thus, clarifying the evolution of the electronic structure with twist angle is critical for understanding the physics of MATBG. Here, we combine nanospot angle-resolved photoemission spectroscopy and atomic force microscopy to resolve the fine electronic structure of the flat band and remote bands, and their evolution with twist angles from 1.07$^\circ$ to 2.60$^\circ$. Near the magic angle, dispersion is characterized by a flat band near the Fermi energy with a strongly reduced bandwidth. Moreover, near 1.07$^\circ$, we observe a spectral weight transfer between remote bands at higher binding energy and extract the modulated interlayer spacing near the magic angle. Our work provides direct spectroscopic information on flat band physics and highlights the role of lattice relaxations.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14078
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Evolution of flat band and role of lattice relaxations in twisted bilayer graphene
Li, Qian
Zhang, Hongyun
Wang, Yijie
Chen, Wanying
Bao, Changhua
Liu, Qinxin
Lin, Tianyun
Zhang, Shuai
Zhang, Haoxiong
Watanabe, Kenji
Taniguchi, Takashi
Avila, Jose
Dudin, Pavel
Li, Qunyang
Yu, Pu
Duan, Wenhui
Song, Zhida
Zhou, Shuyun
Mesoscale and Nanoscale Physics
Materials Science
Magic-angle twisted bilayer graphene (MATBG) exhibits correlated phenomena such as superconductivity and Mott insulating state related to the weakly dispersing flat band near the Fermi energy. Beyond its moiré period, such flat band is expected to be sensitive to lattice relaxations. Thus, clarifying the evolution of the electronic structure with twist angle is critical for understanding the physics of MATBG. Here, we combine nanospot angle-resolved photoemission spectroscopy and atomic force microscopy to resolve the fine electronic structure of the flat band and remote bands, and their evolution with twist angles from 1.07$^\circ$ to 2.60$^\circ$. Near the magic angle, dispersion is characterized by a flat band near the Fermi energy with a strongly reduced bandwidth. Moreover, near 1.07$^\circ$, we observe a spectral weight transfer between remote bands at higher binding energy and extract the modulated interlayer spacing near the magic angle. Our work provides direct spectroscopic information on flat band physics and highlights the role of lattice relaxations.
title Evolution of flat band and role of lattice relaxations in twisted bilayer graphene
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2403.14078