Does Moire Matter? Critical Moire Dependence with Quantum Fluctuations in Graphene Based Integer and Fractional Chern Insulators

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Main Authors: Huo, Zihao, Wang, Wenxuan, Xie, Jian, Kwan, Yves H., Herzog-Arbeitman, Jonah, Zhang, Zaizhe, Yang, Qiu, Wu, Min, Watanabe, Kenji, Taniguchi, Takashi, Liu, Kaihui, Regnault, Nicolas, Bernevig, B. Andrei, Lu, Xiaobo
Format: Preprint
Published: 2025
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author Huo, Zihao
Wang, Wenxuan
Xie, Jian
Kwan, Yves H.
Herzog-Arbeitman, Jonah
Zhang, Zaizhe
Yang, Qiu
Wu, Min
Watanabe, Kenji
Taniguchi, Takashi
Liu, Kaihui
Regnault, Nicolas
Bernevig, B. Andrei
Lu, Xiaobo
author_facet Huo, Zihao
Wang, Wenxuan
Xie, Jian
Kwan, Yves H.
Herzog-Arbeitman, Jonah
Zhang, Zaizhe
Yang, Qiu
Wu, Min
Watanabe, Kenji
Taniguchi, Takashi
Liu, Kaihui
Regnault, Nicolas
Bernevig, B. Andrei
Lu, Xiaobo
contents Rhombohedral multilayer graphene has emerged as a powerful platform for investigating flat-band-driven correlated phenomena, yet most aspects remain not understood. In this work, we systematically study the moire-dependent band topology in rhombohedral hexalayer graphene. For the first time we demonstrate that the moire twist angle plays a crucial role in the formation of the moire Chern insulators in rhombohedral hexalayer graphene/hexagonal boron nitride (RHG/hBN) moire superlattices. In the moire-distant regime at filling factor v = 1, only systems with a twist angle θ < 1.1° exhibit an integer moire Chern insulator, while the fractional Chern insulator at v = 2/3 requires smaller twist angle to be stabilized. Our theoretical modelling, which includes quantum fluctuations and exact diagonalization results, suggests that mean-field theory, which has been widely adopted, does not explain the twist-angle dependence of the v = 1 phase diagram, and that correlation effects are crucial. Moreover, we realize two distinct stacking configurations ( /Xi=0 and /Xi=1) between graphene and hBN, and find that both cases can yield a Chern insulator at v = 1. Our experimental work upends the current mean-field paradigm, illuminates how quantum fluctuations and moiré effects shape the RHG/hBN phase diagram, and paves the way for future understanding and engineering of topological correlated states in rhombohedral graphene moire systems.
format Preprint
id arxiv_https___arxiv_org_abs_2510_15309
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Does Moire Matter? Critical Moire Dependence with Quantum Fluctuations in Graphene Based Integer and Fractional Chern Insulators
Huo, Zihao
Wang, Wenxuan
Xie, Jian
Kwan, Yves H.
Herzog-Arbeitman, Jonah
Zhang, Zaizhe
Yang, Qiu
Wu, Min
Watanabe, Kenji
Taniguchi, Takashi
Liu, Kaihui
Regnault, Nicolas
Bernevig, B. Andrei
Lu, Xiaobo
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Rhombohedral multilayer graphene has emerged as a powerful platform for investigating flat-band-driven correlated phenomena, yet most aspects remain not understood. In this work, we systematically study the moire-dependent band topology in rhombohedral hexalayer graphene. For the first time we demonstrate that the moire twist angle plays a crucial role in the formation of the moire Chern insulators in rhombohedral hexalayer graphene/hexagonal boron nitride (RHG/hBN) moire superlattices. In the moire-distant regime at filling factor v = 1, only systems with a twist angle θ < 1.1° exhibit an integer moire Chern insulator, while the fractional Chern insulator at v = 2/3 requires smaller twist angle to be stabilized. Our theoretical modelling, which includes quantum fluctuations and exact diagonalization results, suggests that mean-field theory, which has been widely adopted, does not explain the twist-angle dependence of the v = 1 phase diagram, and that correlation effects are crucial. Moreover, we realize two distinct stacking configurations ( /Xi=0 and /Xi=1) between graphene and hBN, and find that both cases can yield a Chern insulator at v = 1. Our experimental work upends the current mean-field paradigm, illuminates how quantum fluctuations and moiré effects shape the RHG/hBN phase diagram, and paves the way for future understanding and engineering of topological correlated states in rhombohedral graphene moire systems.
title Does Moire Matter? Critical Moire Dependence with Quantum Fluctuations in Graphene Based Integer and Fractional Chern Insulators
topic Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2510.15309