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Layer-engineered quantum anomalous Hall effect in twisted rhombohedral graphene
Zhangyuan Chen1,2, Naitian Liu1,2, Jiannan Hua1,2
1Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, China.
Nature Materials
|August 14, 2026
Summary
Researchers developed a new quantum anomalous Hall (QAH) insulator using twisted rhombohedral graphene. The layer number directly controls the Chern number, enabling programmable topological states and electrical tuning.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Physics
Background:
- Programmable topological states in quantum anomalous Hall (QAH) insulators are crucial for advanced electronic applications.
- Tuning the topological invariant, the Chern number (C), is essential for realizing such states.
Purpose of the Study:
- To establish a novel QAH platform using twisted rhombohedral graphene.
- To demonstrate electrical tunability of the Chern number (C) in these QAH states.
Main Methods:
- Utilized twisted monolayer-multilayer (1+N) rhombohedral graphene structures.
- Investigated QAH states with Chern numbers C=N for N=3, 4, 5.
- Employed in situ electrical control via electrostatic doping and displacement fields.
Main Results:
- Demonstrated that the layer number N directly sets the Chern number C in twisted rhombohedral graphene.
- Showcased electrical switching of the Chern number sign in a twisted monolayer-trilayer device.
- Observed displacement-field-induced topological phase transitions between QAH states with C=3 and C=4.
Conclusions:
- Established a layer-engineered and electrically tunable platform for QAH insulators.
- This platform enables on-demand engineering of correlated topological states.
- Opens new avenues for designing next-generation topological quantum devices.
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