Observation of even denominator fractional quantum hall effect in suspended bilayer graphene

Dong Keun Ki, Vladimir I. Fal'Ko, Dmitry A. Abanin, Alberto F. Morpurgo

Research output: Contribution to journalArticlepeer-review

112 Scopus citations

Abstract

We investigate low-temperature magneto-transport in recently developed, high-quality multiterminal suspended bilayer graphene devices, enabling the independent measurement of the longitudinal and transverse resistance. We observe clear signatures of the fractional quantum Hall effect with different states that are either fully developed, and exhibit a clear plateau in the transverse resistance with a concomitant dip in longitudinal resistance or incipient, and exhibit only a longitudinal resistance minimum. All observed states scale as a function of filling factor ν, as expected. An unprecedented even-denominator fractional state is observed at ν = -1/2 on the hole side, exhibiting a clear plateau in Rxy quantized at the expected value of 2h/e2 with a precision of ∼0.5%. Many of our observations, together with a recent electronic compressibility measurement performed in graphene bilayers on hexagonal boron-nitride (hBN) substrates, are consistent with a recent theory that accounts for the effect of the degeneracy between the N = 0 and N = 1 Landau levels in the fractional quantum Hall effect and predicts the occurrence of a Moore-Read type ν = -1/2 state. Owing to the experimental flexibility of bilayer graphene, which has a gate-dependent band structure, can be easily accessed by scanning probes, and can be contacted with materials such as superconductors, our findings offer new possibilities to explore the microscopic nature of even-denominator fractional quantum Hall effect.

Original languageEnglish (US)
Pages (from-to)2135-2139
Number of pages5
JournalNano Letters
Volume14
Issue number4
DOIs
StatePublished - Apr 9 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • General Materials Science

Keywords

  • Even-denominator fractional quantum Hall effect
  • Non-Abelian Moore-Read state
  • multiterminal suspended bilayer graphene

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