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説明:

The fractional quantum anomalous Hall effect (FQAHE), the analog of the fractional quantum Hall effect at zero magnetic field, is predicted to exist in topological flat bands under spontaneous time-reversal-symmetry breaking. The demonstration of FQAHE could lead to non-Abelian anyons which form the basis of topological quantum computation. So far, FQAHE has been observed only in twisted MoTe₂ at moiré filling factor v > 1/2. Graphene-based moiré superlattices are believed to host FQAHE with the potential advantage of superior material quality and higher electron mobility. Here we report the observation of integer and fractional QAH effects in a rhombohedral pentalayer graphene/hBN moiré superlattice. At zero magnetic field, we observed plateaus of quantized Hall resistance R_xy = h/ve² at v = 1, 2/3, 3/5, 4/7, 4/9, 3/7 and 2/5 of the moiré superlattice respectively, accompanied by clear dips in the longitudinal resistance R_xx. R_xy equals 2h/e² at v = 1/2 and varies linearly with v — similar to the composite Fermi liquid (CFL) in the half-filled lowest Landau level at high magnetic fields. By tuning the gate displacement field D and v, we observed phase transitions from CFL and FQAH states to other correlated electron states. Our system provides an ideal platform for exploring charge fractionalization and (non-Abelian) anyonic braiding at zero magnetic field, especially considering a lateral junction between FQAHE and superconducting regions in the same device.

権利情報:

• 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: http://dx.doi.org/10.1038/s41586-023-07010-7

キーワード: Fractional quantum anomalous Hall effect (FQAHE), Topological flat bands, Non-Abelian anyons

刊行年月日: 2024-02-22

出版者: Springer Science and Business Media LLC

掲載誌:

• Nature (ISSN: 00280836) vol. 626 issue. 8000 p. 759-764

研究助成金:

原稿種別: 著者最終稿 (Accepted manuscript)

MDR DOI:

公開URL: https://doi.org/10.1038/s41586-023-07010-7

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更新時刻: 2025-09-02 08:30:29 +0900

MDRでの公開時刻: 2025-09-02 08:17:17 +0900