作用于 rhombohedral 石墨超晶格的可调分数 Chern 绝缘体
摘要
分数 Chern 绝缘体 (FCIs) 显示在零磁场下出现分数量化霍尔台阶的传输效应，为工程拓扑量子电子提供了根本性的新机会。通过构建具有 moiré 工程的拓扑平坦带，已在扭曲 MoTe2 系统和 rhombohedral 五层石墨/hBN moiré 超晶格中观察到包含 C <= 2/3 的异常霍尔电阻率量化数，包括 gapless 复合费米液态 C = 1/2。 Here, we experimentally demonstrate a new system of rhombohedral hexalayer graphene (RHG)/hBN moire superlattices, which exhibit both integer and fractional quantum anomalous Hall effects with rich tunability including electric displacement field, perpendicular magnetic field and in-plane magnetic field. By tuning the electrical and magnetic fields at 0 < v < 1, we have observed a quantum phase transition showing a sign reversal of the Hall resistivity at finite magnetic fields. Surprisingly, the FCI state at v = 2/3 survives in the phase transitions, exhibiting a robust quantized Hall resistivity across both phases. Finally we have further demonstrated the indispensable role moire potential plays in the formation of the flat Chern band from a theoretical perspective. Our work has established RHG/hBN moire superlattices as a promising platform for exploring quasi-particles with fractional charge and non-Abelian anyons at zero magnetic field.
引用
@article{arxiv.2405.16944,
title = {Tunable Fractional Chern Insulators in Rhombohedral Graphene Superlattices},
author = {Jian Xie and Zihao Huo and Xin Lu and Zuo Feng and Zaizhe Zhang and Wenxuan Wang and Qiu Yang and Kenji Watanabe and Takashi Taniguchi and Kaihui Liu and Zhida Song and X. C. Xie and Jianpeng Liu and Xiaobo Lu},
journal= {arXiv preprint arXiv:2405.16944},
year = {2025}
}