Correlated states in doubly-aligned hBN/graphene/hBN heterostructures

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; Jianpeng Liu; Yu Ye; Zheng Vitto Han; Zhidong Zhang

doi:10.1038/s41467-021-27514-y

Correlated states in doubly-aligned hBN/graphene/hBN heterostructures

Nat Commun. 2021 Dec 10;12(1):7196. doi: 10.1038/s41467-021-27514-y.

Authors

Xingdan Sun^#^{1

2}, Shihao Zhang^#^{3

4}, Zhiyong Liu^#^{1

2}, Honglei Zhu^{1

2}, Jinqiang Huang^{1

2}, Kai Yuan^{5

6}, Zhenhua Wang^{7

8}, Kenji Watanabe⁹, Takashi Taniguchi¹⁰, Xiaoxi Li^{1

2

11

12}, Mengjian Zhu¹³, Jinhai Mao¹⁴, Teng Yang^{1

2}, Jun Kang¹⁵, Jianpeng Liu^{16

17}, Yu Ye^{18

19}, Zheng Vitto Han^{20

21}, Zhidong Zhang^{1

2}

Affiliations

¹ Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang, China.
² School of Material Science and Engineering, University of Science and Technology of China, 230026, Anhui, China.
³ School of Physical Science and Technology, ShanghaiTech University, 200031, Shanghai, China.
⁴ ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 200031, Shanghai, China.
⁵ State Key Lab for Mesoscopic Physics, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, 100871, Beijing, China.
⁶ Collaborative Innovation Center of Quantum Matter, 100871, Beijing, China.
⁷ Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang, China. zhwang@imr.ac.cn.
⁸ School of Material Science and Engineering, University of Science and Technology of China, 230026, Anhui, China. zhwang@imr.ac.cn.
⁹ Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
¹⁰ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
¹¹ State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, 030006, Taiyuan, China.
¹² Collaborative Innovation Center of Extreme Optics, Shanxi University, 030006, Taiyuan, China.
¹³ College of Advanced Interdisciplinary Studies, National University of Defense Technology, 410073, Changsha, China.
¹⁴ School of Physical Sciences and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China.
¹⁵ Beijing Computational Science Research Center, 100193, Beijing, China. jkang@csrc.ac.cn.
¹⁶ School of Physical Science and Technology, ShanghaiTech University, 200031, Shanghai, China. liujp@shanghaitech.edu.cn.
¹⁷ ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 200031, Shanghai, China. liujp@shanghaitech.edu.cn.
¹⁸ State Key Lab for Mesoscopic Physics, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, 100871, Beijing, China. ye_yu@pku.edu.cn.
¹⁹ Collaborative Innovation Center of Quantum Matter, 100871, Beijing, China. ye_yu@pku.edu.cn.
²⁰ State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, 030006, Taiyuan, China. vitto.han@gmail.com.
²¹ Collaborative Innovation Center of Extreme Optics, Shanxi University, 030006, Taiyuan, China. vitto.han@gmail.com.

^# Contributed equally.

Abstract

Interfacial moiré superlattices in van der Waals vertical assemblies effectively reconstruct the crystal symmetry, leading to opportunities for investigating exotic quantum states. Notably, a two-dimensional nanosheet has top and bottom open surfaces, allowing the specific case of doubly aligned super-moiré lattice to serve as a toy model for studying the tunable lattice symmetry and the complexity of related electronic structures. Here, we show that by doubly aligning a graphene monolayer to both top and bottom encapsulating hexagonal boron nitride (h-BN), multiple conductivity minima are observed away from the main Dirac point, which are sensitively tunable with respect to the small twist angles. Moreover, our experimental evidences together with theoretical calculations suggest correlated insulating states at integer fillings of -5, -6, -7 electrons per moiré unit cell, possibly due to inter-valley coherence. Our results provide a way to construct intriguing correlations in 2D electronic systems in the weak interaction regime.