中国物理B ›› 2024, Vol. 33 ›› Issue (6): 67301-067301.doi: 10.1088/1674-1056/ad3b8a

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Field induced Chern insulating states in twisted monolayer-bilayer graphene

Zhengwen Wang(王政文)1,2, Yingzhuo Han(韩英卓)1, Kenji Watanabe3, Takashi Taniguchi3, Yuhang Jiang(姜宇航)2,†, and Jinhai Mao(毛金海)1,‡   

  1. 1 School of Physical Science and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China;
    2 College of Materials Science and Optoelectronic Technology, Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
    3 Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan
  • 收稿日期:2024-03-09 修回日期:2024-04-07 接受日期:2024-04-07 出版日期:2024-06-18 发布日期:2024-06-18
  • 通讯作者: Yuhang Jiang, Jinhai Mao E-mail:yuhangjiang@ucas.ac.cn;jhmao@ucas.ac.cn

Field induced Chern insulating states in twisted monolayer-bilayer graphene

Zhengwen Wang(王政文)1,2, Yingzhuo Han(韩英卓)1, Kenji Watanabe3, Takashi Taniguchi3, Yuhang Jiang(姜宇航)2,†, and Jinhai Mao(毛金海)1,‡   

  1. 1 School of Physical Science and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China;
    2 College of Materials Science and Optoelectronic Technology, Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
    3 Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan
  • Received:2024-03-09 Revised:2024-04-07 Accepted:2024-04-07 Online:2024-06-18 Published:2024-06-18
  • Contact: Yuhang Jiang, Jinhai Mao E-mail:yuhangjiang@ucas.ac.cn;jhmao@ucas.ac.cn

摘要: Unraveling the mechanism underlying topological phases, notably the Chern insulators (ChIs) in strong correlated systems at the microscopy scale, has captivated significant research interest. Nonetheless, ChIs harboring topological information have not always manifested themselves, owing to the constraints imposed by displacement fields in certain experimental configurations. In this study, we employ density-tuned scanning tunneling microscopy (DT-STM) to investigate the ChIs in twisted monolayer-bilayer graphene (tMBG). At zero magnetic field, we observe correlated metallic states. While under a magnetic field, a metal-insulator transition happens and an integer ChI is formed emanating from the filling index $ s = 3$ with a Chern number $C = 1$. Our results underscore the pivotal role of magnetic fields as a powerful probe for elucidating topological phases in twisted Van der Waals heterostructures.

关键词: Chern insulators, strong correlation effects, two-dimensional van der Waals heterostructure, density-tuned scanning tunneling microscopy (DT-STM)

Abstract: Unraveling the mechanism underlying topological phases, notably the Chern insulators (ChIs) in strong correlated systems at the microscopy scale, has captivated significant research interest. Nonetheless, ChIs harboring topological information have not always manifested themselves, owing to the constraints imposed by displacement fields in certain experimental configurations. In this study, we employ density-tuned scanning tunneling microscopy (DT-STM) to investigate the ChIs in twisted monolayer-bilayer graphene (tMBG). At zero magnetic field, we observe correlated metallic states. While under a magnetic field, a metal-insulator transition happens and an integer ChI is formed emanating from the filling index $ s = 3$ with a Chern number $C = 1$. Our results underscore the pivotal role of magnetic fields as a powerful probe for elucidating topological phases in twisted Van der Waals heterostructures.

Key words: Chern insulators, strong correlation effects, two-dimensional van der Waals heterostructure, density-tuned scanning tunneling microscopy (DT-STM)

中图分类号:  (Electronic structure of graphene)

  • 73.22.Pr
73.21.Cd (Superlattices) 68.37.Ef (Scanning tunneling microscopy (including chemistry induced with STM)) 85.30.Tv (Field effect devices)