Twisted Rhombohedral Graphene Yields C=7/3 Fractional Chern Insulator and High-Chern States up to |C|=7
Updated
Updated · Nature.com · Jul 15
Twisted Rhombohedral Graphene Yields C=7/3 Fractional Chern Insulator and High-Chern States up to |C|=7
1 articles · Updated · Nature.com · Jul 15
Summary
Researchers reported an exotic fractional Chern insulator with C=7/3 near moiré filling ν=2/3 in a twisted rhombohedral graphene system made from Bernal bilayer and rhombohedral tetralayer graphene.
Transport measurements at 10 mK also revealed quantum anomalous Hall insulators spanning |C|=1 to |C|=7 at ν=1 and around ν=3, showing an unusually rich high-Chern phase diagram.
The C=7/3 state sits beyond known fractional Chern insulators described by the Jain sequence or current high-Chern theory, making it a candidate for physics not captured by established frameworks.
The result broadens zero-magnetic-field studies of fractionally charged excitations and points to moiré graphene as a platform for probing anyons and other topological quantum states.
New fractional particles defy all known theories. What fundamental laws of nature are we missing?
An 'impossible' quantum state was just discovered. Could it unlock fault-tolerant quantum computing?
High-Chern-Number Fractional Chern Insulators and Quantum Anomalous Hall States in Twisted Rhombohedral Graphene
Overview
Between 2025 and 2026, researchers made a breakthrough by discovering exotic topological states in graphene, specifically in twisted rhombohedral structures. They achieved high-Chern-number fractional Chern insulators and quantum anomalous Hall states, with a record Chern number of 7. These new states not only reached unprecedented critical temperatures but also showed remarkable stability, making them promising for practical applications. The ability to realize such robust and tunable quantum phases at accessible temperatures opens exciting possibilities for advanced quantum devices and energy-efficient electronics, marking a major step forward in condensed matter physics.