Next-generation even-denominator fractional quantum Hall states of interacting composite fermions

Chengyu Wang, Adbhut Gupta, Pranav T. Madathil, Siddharth K. Singh, Yoon Jang Chung, Loren N. Pfeiffer, Kirk W. Baldwin, Mansour Shayegan

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The discovery of the fractional quantum Hall state (FQHS) in 1982 ushered a new era of research in many-body condensed matter physics. Among the numerous FQHSs, those observed at even-denominator Landau level filling factors are of particular interest as they may host quasiparticles obeying non-Abelian statistics and be of potential use in topological quantum computing. The even-denominator FQHSs, however, are scarce and have been observed predominantly in low-disorder two-dimensional (2D) systems when an excited electron Landau level is half filled. An example is the well-studied FQHS at filling factor ν =5/2 which is believed to be a Bardeen-Cooper- Schrieffer-type, paired state of flux-particle composite fermions (CFs). Here, we report the observation of even-denominator FQHSs at ν = 3/10, 3/8, and 3/4 in the lowest Landau level of an ultrahigh-quality GaAs 2D hole system, evinced by deep minima in longitudinal resistance and developing quantized Hall plateaus. Quite remarkably, these states can be interpreted as even-denominator FQHSs of CFs, emerging from pairing of higher-order CFs when a CF Landau level, rather than an electron or a hole Landau level, is half-filled. Our results affirm enhanced interaction between CFs in a hole system with significant Landau level mixing and, more generally, the pairing of CFs as a valid mechanism for even-denominator FQHSs, and suggest the realization of FQHSs with non-Abelian anyons.

Original languageEnglish (US)
Article numbere2314212120
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number52
StatePublished - 2023
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


  • Landau level mixing
  • composite fermion pairing
  • even denominator
  • fractional quantum Hall effect
  • lowest Landau level


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