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The recent observation of the fractional quantum anomalous Hall effect in moiré fractional Chern insulators provides an opportunity to investigate zero magnetic field anyons. One approach for potentially realizing non-abelian anyons is to engineer higher flat Chern bands that mimic higher Landau levels. We investigate the interaction, topology and ferromagnetism of the second moiré miniband in twisted MoTe2 bilayers. At half-filling of the second miniband, we observed spontaneous ferromagnetism and an incipient Chern insulator state. The Chern numbers of the top two moiré flat bands exhibited opposite signs for twist angles above 3.1° but had the same sign near 2.6°, consistent with theoretical predictions. In the 2.6° device, increasing the magnetic field induced a topological phase transition due to band-crossing between opposite valleys, resulting in an emergent state with Chern number C = −2. Additionally, an insulating state at half-filling of the second valley-polarized band indicates that a charge-ordered state is favoured over the fractional Chern insulator state. These findings lay a foundation for understanding the higher flat Chern bands, which are crucial for the discovery of non-abelian fractional Chern insulators.

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• In Copyright
  

  This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1038/s41567-025-02804-0.

Keyword: Fractional Chern insulators, Twisted MoTe2 bilayers, Non-abelian anyons

Date published: 2025-03-20

Publisher: Springer Science and Business Media LLC

Journal:

• Nature Physics (ISSN: 17452481) vol. 21 issue. 4 p. 549-555

Funding:

• DOE | SC | Basic Energy Sciences DE-SC0018171
• DOE | SC | Basic Energy Sciences DE-SC0019443
• United States Department of Defense | United States Air Force | AFMC | Air Force Office of Scientific Research AFOSR FA9550-21-1-0177
• NSF | Directorate for Education & Human Resources | Division of Graduate Education DGE-2140004
• MEXT | Japan Society for the Promotion of Science 21H05233, 23H02052
• MEXT | Japan Society for the Promotion of Science KAKENHI 21H05233, 23H02052
• Simons Foundation Simons Investigator Grant No. 404513

Manuscript type: Author's version (Accepted manuscript)

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First published URL: https://doi.org/10.1038/s41567-025-02804-0

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Updated at: 2026-07-03 15:15:10 +0900

Published on MDR: 2026-07-03 16:29:22 +0900