Year: 2021
Type: article
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.
Source: Nature Communications
Institutions: University of Science and Technology of China, Chinese Academy of Sciences, Institute of Metal Research, Shenyang National Laboratory for Materials Science, ShanghaiTech University, Peking University, Collaborative Innovation Center of Quantum Matter, National Institute for Materials Science, Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices, National University of Defense Technology, University of Chinese Academy of Sciences, Beijing Computational Science Research Center, Ministry of Education of the People's Republic of China
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $5,560
OpenAlex ID: W4200037934