Quantum Phase Transitions and Fractional Quantized Anomalous Hall Insulators in Rhombohedral Graphene
Abstract
Fractional quantum anomalous Hall effect (FQAHE) has been discovered in twisted MoTe2 and rhombohedral graphene/hBN moiré superlattices. Such van der Waals heterostructures feature a tuning knob of gate displacement field D, which is absent from the conventional fractional quantum Hall systems in two-dimensional electron gases. D plays a critical role in engineering FQAHE and other emergent quantum states and provides an exciting new opportunity to explore their quantum phase transitions. However, the microscopic details of such transitions and temperature-dependent transport have remained mostly elusive. Here we report systematic resistance measurements in rhombohedral pentalayer graphene/hBN moiré superlattices. We found that the displacement field-driven phase transitions between Composite Fermi liquid, Fermi liquid, Fractional Chern insulators, and insulating states are described by semi-circle relations of the longitudinal and transverse resistivities (or conductivities), largely unexplored in the fractional quantum Hall systems. This agrees with a spatially separated two-phase picture for the phase transitions and further indicates a new insulator phase--fractional quantized anomalous Hall insulator. By comparing the temperature-dependence of longitudinal resistance with the thermal activation model, we estimated the transport gap sizes in three fractional Chern insulator states. Our work shed light on the quantum and temperature evolutions of fractional Chern insulator states--providing necessary background for anyon-braiding and gate-defined junctions in rhombohedral graphene.
Related
- Composite Fermion Theory of Fractional Chern Insulators in Rhombohedral Graphene
- Transdimensional Chern insulators in rhombohedral multilayer graphene superlattices
- Spin-polarized Superconductivity and High-Chern Insulators in Twisted Rhombohedral Graphene Family
- Coexistence of Superconductivity and Chern insulators with |C| ≥ 1 in twisted rhombohedral bilayer-trilayer graphene
- Quantized Transport in Floquet Topological Insulators
BibTeX
@misc{hadjri2026quantum,
title = {{Quantum Phase Transitions and Fractional Quantized Anomalous Hall Insulators in Rhombohedral Graphene}},
author = {Zach Hadjri and Xinlei Yue and Tonghang Han and Yuxuan Yao and Zhengguang Lu and Shenyong Ye and Junseok Seo and Jixiang Yang and Kenji Watanabe and Takashi Taniguchi and Liang Fu and Ady Stern and Long Ju},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.09422},
eprint = {2609.09422},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.09422},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Quantum Phase Transitions and Fractional Quantized Anomalous Hall Insulators in Rhombohedral Graphene
AU - Zach Hadjri
AU - Xinlei Yue
AU - Tonghang Han
AU - Yuxuan Yao
AU - Zhengguang Lu
AU - Shenyong Ye
AU - Junseok Seo
AU - Jixiang Yang
AU - Kenji Watanabe
AU - Takashi Taniguchi
AU - Liang Fu
AU - Ady Stern
AU - Long Ju
PY - 2026
DA - 2026/09/08
PB - arXiv
DO - 10.48550/arxiv.2609.09422
UR - https://arxiv.org/abs/2609.09422
AB - Fractional quantum anomalous Hall effect (FQAHE) has been discovered in twisted MoTe_2 and rhombohedral graphene/hBN moiré superlattices. Such van der Waals heterostructures feature a tuning knob of gate displacement field D, which is absent from the conventional fractional quantum Hall systems in two-dimensional electron gases. D plays a critical role in engineering FQAHE and other emergent quantum states and provides an exciting new opportunity to explore their quantum phase transitions. However, the microscopic details of such transitions and temperature-dependent transport have remained mostly elusive. Here we report systematic resistance measurements in rhombohedral pentalayer graphene/hBN moiré superlattices. We found that the displacement field-driven phase transitions between Composite Fermi liquid, Fermi liquid, Fractional Chern insulators, and insulating states are described by semi-circle relations of the longitudinal and transverse resistivities (or conductivities), largely unexplored in the fractional quantum Hall systems. This agrees with a spatially separated two-phase picture for the phase transitions and further indicates a new insulator phase--fractional quantized anomalous Hall insulator. By comparing the temperature-dependence of longitudinal resistance with the thermal activation model, we estimated the transport gap sizes in three fractional Chern insulator states. Our work shed light on the quantum and temperature evolutions of fractional Chern insulator states--providing necessary background for anyon-braiding and gate-defined junctions in rhombohedral graphene.
ER -