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

被引：12

作者：

Li, Qian ^{[1
,2
]}

Zhang, Hongyun ^{[1
,2
]}

Wang, Yijie ^{[3
]}

Chen, Wanying ^{[1
,2
]}

Bao, Changhua ^{[1
,2
]}

Liu, Qinxin ^{[1
,2
]}

Lin, Tianyun ^{[1
,2
]}

Zhang, Shuai ^{[4
]}

Zhang, Haoxiong ^{[1
,2
]}

Watanabe, Kenji ^{[5
]}

Taniguchi, Takashi ^{[6
]}

Avila, Jose ^{[7
]}

Dudin, Pavel ^{[7
]}

Li, Qunyang ^{[4
]}

Yu, Pu ^{[1
,2
,8
]}

Duan, Wenhui ^{[1
,2
,8
,9
]}

Song, Zhida ^{[3
]}

Zhou, Shuyun ^{[1
,2
,8
]}

机构：

[1] Tsinghua Univ, State Key Lab Low Dimens Quantum Phys, Beijing, Peoples R China

[2] Tsinghua Univ, Dept Phys, Beijing, Peoples R China

[3] Peking Univ, Int Ctr Quantum Mat, Sch Phys, Beijing, Peoples R China

[4] Tsinghua Univ, Dept Engn Mech, AML, CNMM, Beijing, Peoples R China

[5] Natl Inst Mat Sci, Res Ctr Funct Mat, Tsukuba, Japan

[6] Natl Inst Mat Sci, Int Ctr Mat Nanoarchitecton, Tsukuba, Japan

[7] Orme Merisiers, Synchrotron SOLEIL, Gif Sur Yvette, France

[8] Frontier Sci Ctr Quantum Informat, Beijing, Peoples R China

[9] Tsinghua Univ, Inst Adv Study, Beijing, Peoples R China

来源：

NATURE MATERIALS | 2024年 / 23卷 / 08期

基金：

中国国家自然科学基金; 国家重点研发计划; 中国博士后科学基金;

关键词：

MAGIC-ANGLE; MOIRE BANDS;

D O I：

10.1038/s41563-024-01858-4

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Magic-angle twisted bilayer graphene exhibits correlated phenomena such as superconductivity and Mott insulating states related to the weakly dispersing flat band near the Fermi energy. Such a flat band is expected to be sensitive to both the moir & eacute; period and lattice relaxations. Thus, clarifying the evolution of the electronic structure with the twist angle is critical for understanding the physics of magic-angle twisted bilayer graphene. Here we combine nano-spot angle-resolved photoemission spectroscopy and atomic force microscopy to resolve the fine electronic structure of the flat band and remote bands, as well as their evolution with twist angle from 1.07 degrees to 2.60 degrees. Near the magic angle, the dispersion is characterized by a flat band near the Fermi energy with a strongly reduced band width. Moreover, we observe a spectral weight transfer between remote bands at higher binding energy, which allows to extract the modulated interlayer spacing near the magic angle. Our work provides direct spectroscopic information on flat band physics and highlights the important role of lattice relaxations. By combining nano-spot angle-resolved photoemission spectroscopy and atomic force microscopy, the authors resolve the fine electronic structure of the flat band and remote bands of twisted bilayer graphene as the twist angle varies, revealing a spectral weight transfer between remote bands that is attributed to lattice relaxations.

引用

页码：1070 / 1076

页数：19

共 46 条

[1] Emergent D6 symmetry in fully relaxed magic-angle twisted bilayer graphene [J].

Angeli, M. ;

Mandelli, D. ;

Valli, A. ;

Amaricci, A. ;

Capone, M. ;

Tosatti, E. ;

Fabrizio, M. .

PHYSICAL REVIEW B, 2018, 98 (23)

[2] Stacking-Dependent Electronic Structure of Trilayer Graphene Resolved by Nanospot Angle-Resolved Photoemission Spectroscopy [J].

Bao, Changhua ;

Yao, Wei ;

Wang, Eryin ;

Chen, Chaoyu ;

Avila, Jose ;

Asensio, Maria C. ;

Zhou, Shuyun .

NANO LETTERS, 2017, 17 (03) :1564-1568

[3] Moire bands in twisted double-layer graphene [J].

Bistritzer, Rafi ;

MacDonald, Allan H. .

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2011, 108 (30) :12233-12237

[4] Structural relaxation and low-energy properties of twisted bilayer graphene [J].

Cantele, Giovanni ;

Alfe, Dario ;

Conte, Felice ;

Cataudella, Vittorio ;

Ninno, Domenico ;

Lucignano, Procolo .

PHYSICAL REVIEW RESEARCH, 2020, 2 (04)

[5] Superlattice-Induced Insulating States and Valley-Protected Orbits in Twisted Bilayer Graphene [J].

Cao, Y. ;

Luo, J. Y. ;

Fatemi, V. ;

Fang, S. ;

Sanchez-Yamagishi, J. D. ;

Watanabe, K. ;

Taniguchi, T. ;

Kaxiras, E. ;

Jarillo-Herrero, P. .

PHYSICAL REVIEW LETTERS, 2016, 117 (11)

[6] Unconventional superconductivity in magic-angle graphene superlattices [J].

Cao, Yuan ;

Fatemi, Valla ;

Fang, Shiang ;

Watanabe, Kenji ;

Taniguchi, Takashi ;

Kaxiras, Efthimios ;

Jarillo-Herrero, Pablo .

NATURE, 2018, 556 (7699) :43-+

[7] Electronic-structure methods for twisted moire layers [J].

Carr, Stephen ;

Fang, Shiang ;

Kaxiras, Efthimios .

NATURE REVIEWS MATERIALS, 2020, 5 (10) :748-763

[8] Exact continuum model for low-energy electronic states of twisted bilayer graphene [J].

Carr, Stephen ;

Fang, Shiang ;

Zhu, Ziyan ;

Kaxiras, Efthimios .

PHYSICAL REVIEW RESEARCH, 2019, 1 (01)

[9]

Choi Y, 2019, NAT PHYS, V15, P1174, DOI 10.1038/s41567-019-0606-5

[10] Angle-resolved photoemission studies of the cuprate superconductors [J].

Damascelli, A ;

Hussain, Z ;

Shen, ZX .

REVIEWS OF MODERN PHYSICS, 2003, 75 (02) :473-541

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