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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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Authors and Affiliations



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).

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