发表机构
Columbia University; Flatiron Institute; Yale University（哥伦比亚大学; 平顿研究所; 耶鲁大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出复合费米子理论，解释菱方石墨烯中分数陈绝缘体态的形成机制，揭示莫尔势与库仑相互作用如何稳定FCI基态，为相关研究提供新框架。
AI 中文摘要
菱方石墨烯多层中分数量子反常霍尔效应的实验观测，引发了关于分数陈绝缘体（FCI）态的本质以及莫尔势作用的疑问。在本信中，我们发展了一种复合费米子（CF）描述，并讨论了莫尔调制和库仑相互作用如何稳定FCI基态。在磁通附着变换和平均场近似下，CF谱形成朗道能级，这些能级进一步被莫尔势分裂。在Jain序列中的莫尔填充分数处，整数个CF带被占据，从而产生具有分数化量子化霍尔响应的不可压缩基态。值得注意的是，当附着的磁通与菱方石墨烯导带的贝里曲率相反时，CF朗道能级在能量上间隔较大且在层间离域，导致态密度降低，这有助于保护CF平均场态，并放大作用于远离掺杂电子的层的莫尔势效应。CF之间的相互作用进一步增大了莫尔诱导的带隙，并稳定了FCI基态。我们的工作阐明了菱方石墨烯中FCI态的本质，并为进一步研究提供了新的理论框架。
英文摘要
The experimental observation of the fractional quantum anomalous Hall effect in rhombohedral graphene multilayers has raised questions about the nature of the fractional Chern insulator (FCI) states and the role of the moiré potential. In this Letter we develop a composite fermion (CF) description and discuss how moiré modulation and Coulomb interactions stabilize the FCI ground states. Under a flux-attachment transformation and mean-field approximation, the CF spectrum forms Landau levels that are further split by the moiré potential. At moiré filling fractions in the Jain sequence, an integer number of CF bands are occupied, resulting in an incompressible ground state with fractionally quantized Hall response. Remarkably, when the attached flux opposes the Berry curvature of the conduction band of rhombohedral graphene, the CF Landau levels are widely spaced in energy and delocalized across layers, leading to a reduced density of states that helps protect the CF mean-field state and amplifying effects of the moiré potential acting on the layer away from the doped electrons. Interactions between CFs further enlarge the moiré-induced band gap and stabilize the FCI ground state. Our work sheds light on the nature of the FCI states in rhombohedral graphene and provides a new theoretical framework for further studies.
