Even denominator fractional quantum Hall states in higher Landau levels of graphene

Youngwook Kim, Ajit C. Balram, Takashi Taniguchi, Kenji Watanabe, Jainendra K. Jain, Jurgen H. Smet

Research output: Contribution to journalLetterpeer-review

28 Scopus citations

Abstract

An important development in the field of the fractional quantum Hall effect was the proposal that the 5/2 state observed in the Landau level with orbital index n = 1 of two-dimensional electrons in a GaAs quantum well 1 originates from a chiral p-wave paired state of composite fermions that are topological bound states of electrons and quantized vortices. The excitations of this state, which is theoretically described by a ‘Pfaffian’ wavefunction 2 or its hole partner called the anti-Pfaffian 3,4 , are neither fermions nor bosons but Majorana quasiparticles obeying non-Abelian braid statistics 5 . This has inspired ideas for fault-tolerant topological quantum computation 6 and has also instigated a search for other states with exotic quasiparticles. Here we report experiments on monolayer graphene that show clear evidence for unexpected even denominator fractional quantum Hall physics in the n = 3 Landau level. We numerically investigate the known candidate states for the even denominator fractional quantum Hall effect, including the Pfaffian, the particle–hole symmetric Pfaffian and the 221-parton states, and conclude that, among these, the 221-parton appears a potentially suitable candidate to describe the experimentally observed state. Like the Pfaffian, this state is believed to harbour quasi-particles with non-Abelian braid statistics 7 .

Original languageEnglish (US)
Pages (from-to)154-158
Number of pages5
JournalNature Physics
Volume15
Issue number2
DOIs
StatePublished - Feb 1 2019

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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