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Fractional quantum Hall (FQH) states are exotic quantum many-body phases whose elementary charged excitations are neither bosons nor fermions but anyons, obeying fractional braiding statistics. While most FQH states are believed to have Abelian anyons, the Moore-Read type states with even denominators, appearing at half filling of a Landau level (LL), are predicted to possess non-Abelian excitations with appealing potentials in topological quantum computation. These states, however, depend sensitively on the orbital contents of the single-particle LL wavefunctions and the mixing between different LLs. Although they have been observed in a few materials, their non-Abelian statistics still awaits experimental confirmation. Here we show magnetotransport measurements on Bernal-stacked trilayer graphene (TLG), whose unique multiband structure facilitates the interlaced LL mixing, which can be controlled by external magnetic and displacement fields. We observe a series of robust FQH states including even-denominator ones at filling factors ν = −9/2, −3/2, 3/2 and 9/2. In addition, we are able to finetune the LL mixing and crossings to drive quantum phase transitions of these half-filling states and their neighboring odd-denominator ones, exhibiting a related emerging and waning behavior. Our results establish TLG as a controllable system for tuning LL orbital contents and their mixing strengths, and a fresh platform to seek for non-Abelian quasi-particles.

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• Creative Commons BY Attribution 4.0 International
  

Keyword: Fractional quantum Hall, non-Abelian excitations, Bernal-stacked trilayer graphene

Date published: 2024-07-24

Publisher: Springer Science and Business Media LLC

Journal:

• Nature Communications (ISSN: 20411723) vol. 15 issue. 1 6236

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Manuscript type: Publisher's version (Version of record)

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First published URL: https://doi.org/10.1038/s41467-024-50589-2

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Updated at: 2025-02-06 12:31:03 +0900

Published on MDR: 2025-02-06 12:31:03 +0900