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Tunable correlated Chern insulator and ferromagnetism in a moiré superlattice

Author

Listed:
  • Guorui Chen

    (Lawrence Berkeley National Laboratory
    University of California at Berkeley)

  • Aaron L. Sharpe

    (Stanford University
    SLAC National Accelerator Laboratory)

  • Eli J. Fox

    (SLAC National Accelerator Laboratory
    Stanford University)

  • Ya-Hui Zhang

    (Massachusetts Institute of Technology)

  • Shaoxin Wang

    (University of California at Berkeley)

  • Lili Jiang

    (University of California at Berkeley)

  • Bosai Lyu

    (Shanghai Jiao Tong University
    Collaborative Innovation Center of Advanced Microstructures)

  • Hongyuan Li

    (Lawrence Berkeley National Laboratory
    University of California at Berkeley)

  • Kenji Watanabe

    (National Institute for Materials Science)

  • Takashi Taniguchi

    (National Institute for Materials Science)

  • Zhiwen Shi

    (Shanghai Jiao Tong University
    Collaborative Innovation Center of Advanced Microstructures)

  • T. Senthil

    (Massachusetts Institute of Technology)

  • David Goldhaber-Gordon

    (SLAC National Accelerator Laboratory
    Stanford University)

  • Yuanbo Zhang

    (Collaborative Innovation Center of Advanced Microstructures
    Fudan University
    Fudan University)

  • Feng Wang

    (Lawrence Berkeley National Laboratory
    University of California at Berkeley
    Kavli Energy NanoSciences Institute at the University of California, Berkeley, and the Lawrence Berkeley National Laboratory)

Abstract

Studies of two-dimensional electron systems in a strong magnetic field revealed the quantum Hall effect1, a topological state of matter featuring a finite Chern number C and chiral edge states2,3. Haldane4 later theorized that Chern insulators with integer quantum Hall effects could appear in lattice models with complex hopping parameters even at zero magnetic field. The ABC-trilayer graphene/hexagonal boron nitride (ABC-TLG/hBN) moiré superlattice provides an attractive platform with which to explore Chern insulators because it features nearly flat moiré minibands with a valley-dependent, electrically tunable Chern number5,6. Here we report the experimental observation of a correlated Chern insulator in an ABC-TLG/hBN moiré superlattice. We show that reversing the direction of the applied vertical electric field switches the moiré minibands of ABC-TLG/hBN between zero and finite Chern numbers, as revealed by large changes in magneto-transport behaviour. For topological hole minibands tuned to have a finite Chern number, we focus on quarter filling, corresponding to one hole per moiré unit cell. The Hall resistance is well quantized at h/2e2 (where h is Planck’s constant and e is the charge on the electron), which implies C = 2, for a magnetic field exceeding 0.4 tesla. The correlated Chern insulator is ferromagnetic, exhibiting substantial magnetic hysteresis and a large anomalous Hall signal at zero magnetic field. Our discovery of a C = 2 Chern insulator at zero magnetic field should open up opportunities for discovering correlated topological states, possibly with topological excitations7, in nearly flat and topologically nontrivial moiré minibands.

Suggested Citation

  • Guorui Chen & Aaron L. Sharpe & Eli J. Fox & Ya-Hui Zhang & Shaoxin Wang & Lili Jiang & Bosai Lyu & Hongyuan Li & Kenji Watanabe & Takashi Taniguchi & Zhiwen Shi & T. Senthil & David Goldhaber-Gordon , 2020. "Tunable correlated Chern insulator and ferromagnetism in a moiré superlattice," Nature, Nature, vol. 579(7797), pages 56-61, March.
    • Handle: RePEc:nat:nature:v:579:y:2020:i:7797:d:10.1038_s41586-020-2049-7
    DOI: 10.1038/s41586-020-2049-7
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    Citations

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    Cited by:

    1. Si, Nan & Guan, Yin-Yan & Gao, Wei-Chun & Guo, An-Bang & Zhang, Yan-Li & Jiang, Wei, 2022. "Ferrimagnetism and reentrant behavior in a coronene-like superlattice with double-layer," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 589(C).
    2. Wenqiang Zhou & Jing Ding & Jiannan Hua & Le Zhang & Kenji Watanabe & Takashi Taniguchi & Wei Zhu & Shuigang Xu, 2024. "Layer-polarized ferromagnetism in rhombohedral multilayer graphene," Nature Communications, Nature, vol. 15(1), pages 1-8, December.
    3. Hao Chen & Arpit Arora & Justin C. W. Song & Kian Ping Loh, 2023. "Gate-tunable anomalous Hall effect in Bernal tetralayer graphene," Nature Communications, Nature, vol. 14(1), pages 1-6, December.
    4. Zeya Li & Junwei Huang & Ling Zhou & Zian Xu & Feng Qin & Peng Chen & Xiaojun Sun & Gan Liu & Chengqi Sui & Caiyu Qiu & Yangfan Lu & Huiyang Gou & Xiaoxiang Xi & Toshiya Ideue & Peizhe Tang & Yoshihir, 2023. "An anisotropic van der Waals dielectric for symmetry engineering in functionalized heterointerfaces," Nature Communications, Nature, vol. 14(1), pages 1-9, December.
    5. Pratap Chandra Adak & Subhajit Sinha & Debasmita Giri & Dibya Kanti Mukherjee & Chandan & L. D. Varma Sangani & Surat Layek & Ayshi Mukherjee & Kenji Watanabe & Takashi Taniguchi & H. A. Fertig & Arij, 2022. "Perpendicular electric field drives Chern transitions and layer polarization changes in Hofstadter bands," Nature Communications, Nature, vol. 13(1), pages 1-8, December.
    6. Martin Claassen & Lede Xian & Dante M. Kennes & Angel Rubio, 2022. "Ultra-strong spin–orbit coupling and topological moiré engineering in twisted ZrS2 bilayers," Nature Communications, Nature, vol. 13(1), pages 1-8, December.
    7. Xiaozhou Zan & Xiangdong Guo & Aolin Deng & Zhiheng Huang & Le Liu & Fanfan Wu & Yalong Yuan & Jiaojiao Zhao & Yalin Peng & Lu Li & Yangkun Zhang & Xiuzhen Li & Jundong Zhu & Jingwei Dong & Dongxia Sh, 2024. "Electron/infrared-phonon coupling in ABC trilayer graphene," Nature Communications, Nature, vol. 15(1), pages 1-6, December.
    8. Le Liu & Shihao Zhang & Yanbang Chu & Cheng Shen & Yuan Huang & Yalong Yuan & Jinpeng Tian & Jian Tang & Yiru Ji & Rong Yang & Kenji Watanabe & Takashi Taniguchi & Dongxia Shi & Jianpeng Liu & Wei Yan, 2022. "Isospin competitions and valley polarized correlated insulators in twisted double bilayer graphene," Nature Communications, Nature, vol. 13(1), pages 1-7, December.
    9. Valerio Di Giulio & P. A. D. Gonçalves & F. Javier García de Abajo, 2022. "An image interaction approach to quantum-phase engineering of two-dimensional materials," Nature Communications, Nature, vol. 13(1), pages 1-8, December.
    10. Junxiong Hu & Junyou Tan & Mohammed M. Al Ezzi & Udvas Chattopadhyay & Jian Gou & Yuntian Zheng & Zihao Wang & Jiayu Chen & Reshmi Thottathil & Jiangbo Luo & Kenji Watanabe & Takashi Taniguchi & Andre, 2023. "Controlled alignment of supermoiré lattice in double-aligned graphene heterostructures," Nature Communications, Nature, vol. 14(1), pages 1-8, December.
    11. Mohit Kumar Jat & Priya Tiwari & Robin Bajaj & Ishita Shitut & Shinjan Mandal & Kenji Watanabe & Takashi Taniguchi & H. R. Krishnamurthy & Manish Jain & Aveek Bid, 2024. "Higher order gaps in the renormalized band structure of doubly aligned hBN/bilayer graphene moiré superlattice," Nature Communications, Nature, vol. 15(1), pages 1-7, December.
    12. Xingdan Sun & Shihao Zhang & Zhiyong Liu & Honglei Zhu & Jinqiang Huang & Kai Yuan & Zhenhua Wang & Kenji Watanabe & Takashi Taniguchi & Xiaoxi Li & Mengjian Zhu & Jinhai Mao & Teng Yang & Jun Kang & , 2021. "Correlated states in doubly-aligned hBN/graphene/hBN heterostructures," Nature Communications, Nature, vol. 12(1), pages 1-8, December.

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