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The fractional quantum anomalous Hall effect

More than 40 years after the discovery of the quantum Hall effect, the investigation of new variants of this phenomenon and of the exotic physics they represent is still a lively research topic. In this Viewpoint, five scientists involved in the very recent discovery of a new type of Hall effect — the fractional quantum anomalous Hall effect — discuss their results and their implications.

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References

  1. Werkmeister, T. et al. Anyon braiding and telegraph noise in a graphene interferometer. Preprint at https://arxiv.org/abs/2403.18983 (2024).

  2. Samuelson, N. L. et al. Anyonic statistics and slow quasiparticle dynamics in a graphene fractional quantum Hall interferometer. Preprint at https://arxiv.org/abs/2403.19628 (2024).

  3. Morales-Durán, N., Wei, N., Shi, J. & MacDonald, A. H. Magic angles and fractional Chern insulators in twisted homobilayer transition metal dichalcogenides. Phys. Rev. Lett. 132, 096602 (2024).

    Article  PubMed  Google Scholar 

  4. Shi, J., Morales-Durán, N., Khalaf, E. & MacDonald, A. H. Adiabatic approximation and Aharonov–Casher bands in twisted homobilayer TMDs. Preprint at https://arxiv.org/abs/2404.13455 (2024).

  5. Fengcheng Wu, T. L., Emanuel, T., Ivar, M. & MacDonald, A. H. Topological insulators in twisted transition metal dichalcogenide homobilayers. Phys. Rev. Lett. 122, 086402 (2019).

    Article  PubMed  Google Scholar 

  6. Dong, J., Wang, J., Ledwith, P. J., Vishwanath, A. & Parker, D. E. Composite Fermi liquid at zero magnetic field in twisted MoTe2. Phys. Rev. Lett. 131, 136502 (2023).

    Article  CAS  PubMed  Google Scholar 

  7. Anderson, E. et al. Programming correlated magnetic states via gate controlled moiré geometry. Science 381, 325 (2023).

    Article  CAS  PubMed  Google Scholar 

  8. Li, H., Kumar, U., Sun, K. & Lin, S.-Z. Spontaneous fractional Chern insulators in transition metal dichalcogenide moiré superlattices. Phys. Rev. Res. 3, L032070 (2021).

    Article  CAS  Google Scholar 

  9. Devakul, T. et al. Magic in twisted transition metal dichalcogenide bilayers. Nat. Commun. 12, 6730 (2021).

    Article  CAS  PubMed  Google Scholar 

  10. Jiaqi, C. et al. Signatures of fractional quantum anomalous Hall states in twisted MoTe2 bilayer. Nature 622, 63–68 (2023).

    Article  Google Scholar 

  11. Park, H. et al. Observation of fractionally quantized anomalous Hall effect. Nature 622, 74–79 (2023).

    Article  CAS  PubMed  Google Scholar 

  12. Ji, Z. et al. Local probe of bulk and edge states in a fractional Chern insulator. Preprint at https://arxiv.org/abs/2404.07157 (2024).

  13. Zeng, Y. et al. Thermodynamic evidence of fractional Chern insulator in moiré MoTe2. Nature 622, 69–73 (2023).

    Article  CAS  PubMed  Google Scholar 

  14. Xia, Z. et al. Optical readout of the chemical potential of two-dimensional electrons. Nat. Photon. 18, 344–349 (2024).

    Article  CAS  Google Scholar 

  15. Kang, K. et al. Evidence of the fractional quantum spin Hall effect in moiré MoTe2. Nature 628, 522–526 (2024).

    Article  CAS  PubMed  Google Scholar 

  16. Lu, Z. et al. Fractional quantum anomalous Hall effect in multilayer graphene. Nature 626, 759–764 (2024).

    Article  CAS  PubMed  Google Scholar 

  17. Han, T. et al. Correlated insulator and Chern insulators in pentalayer rhombohedral-stacked graphene. Nat. Nanotechnol. 19, 181–187 (2024).

    Article  CAS  PubMed  Google Scholar 

  18. Vishwanath, A. Zero field fractional Hall states, now in graphene heterostructures. J. Club Condens. Matter Phys. https://doi.org/10.36471/JCCM_December_2023_03 (2023).

  19. Parameswaran, S. A. Anomalous Hall crystals or moiré Chern insulators? Spontaneous versus explicit translational symmetry breaking in graphene pentalayers. J. Club Condens. Matter Phys. https://doi.org/10.36471/JCCM_January_2024_02 (2024).

  20. Goldman, H., Reddy, A. P., Paul, N. & Fu, L. Zero-field composite Fermi liquid in twisted semiconductor bilayers. Phys. Rev. Lett. 131, 136501 (2023).

    Article  CAS  PubMed  Google Scholar 

Download references

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Authors and Affiliations

Authors

Contributions

Long Ju is an Assistant Professor of Physics at MIT. His group combines advanced electrical and optical techniques to study emergent quantum phenomena in novel quantum materials, in particular 2D materials and their van der Waals heterostructures.

Allan MacDonald is the Sid W. Richardson Foundation Regents Chair Professor of Physics at The University of Texas at Austin. As a theorist, his primary research interests centre on the influence of electron–electron interactions on the electronic properties of metals and semiconductors and on those of moiré materials in particular.

Kin Fai Mak is the Josephson Family Professor in the College of Arts and Sciences at Cornell University. The research group he jointly leads with Jie Shan uses optical and electrical probes to explore condensed matter phenomena in atomically thin materials and their heterostructures.

Jie Shan is the Walter S. Carpenter Professor of Engineering at Cornell University. The research group she jointly leads with Kin Fai Mak uses optical and electrical probes to explore condensed matter phenomena in atomically thin materials and their heterostructures.

Xiaodong Xu is the Boeing Distinguished Professor of Physics and Professor of Materials Science and Engineering at the University of Washington, where he researches magnetism, topology and electron–electron correlations of quantum materials by optical spectroscopy and electrical transport measurements.

Corresponding authors

Correspondence to Long Ju, Allan H. MacDonald, Kin Fai Mak, Jie Shan or Xiaodong Xu.

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The authors declare no competing interests.

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Ju, L., MacDonald, A.H., Mak, K.F. et al. The fractional quantum anomalous Hall effect. Nat Rev Mater 9, 455–459 (2024). https://doi.org/10.1038/s41578-024-00694-x

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