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arXiv · 2502.06245

Even-denominator fractional quantum Hall states in the zeroth Landau level of ABA trilayer graphene

Tanima Chanda·Simrandeep Kaur·Harsimran Singh·Kenji Watanabe·Takashi Taniguchi·Manish Jain·Udit Khanna·Ajit C. Balram·Aveek Bid
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Abstract

Even-denominator fractional quantum Hall states (FQHSs) at half filling are of particular interest because they can host non-Abelian quasiparticles. Here we report the emergence of such states in the zeroth Landau level ($N=0$) of ABA trilayer graphene (TLG), challenging the conventional expectation that they are confined to the first excited Landau level. We observe robust incompressible states at $\nu=7/2$, $9/2$, and $5/2$ with their associated Levin--Halperin daughter states: $\nu=59/17$ and $46/13$ near $7/2$; $\nu=58/13$ and $77/17$ near $9/2$; and $\nu=43/17$ near $5/2$. These states appear exclusively within a finite displacement-field window coincident with crossings between symmetry-broken $N=0$ Landau levels carrying distinct isospin indices. The quantitative correspondence between the calculated crossing loci and the experimentally determined stability regions identifies Landau-level mixing as the microscopic origin. We attribute the stabilization of these even-denominator states to inversion-symmetry breaking in TLG, which enhances valley-resolved Landau-level hybridization and renormalizes short-range Coulomb interactions. Our results expand the landscape of even-denominator FQHSs to multilayer graphene and establish TLG as a tunable platform for realizing non-Abelian anyons.

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Tanima Chanda, Simrandeep Kaur, Harsimran Singh, Kenji Watanabe, Takashi Taniguchi, Manish Jain, Udit Khanna, Ajit C. Balram, Aveek Bid. 2025-02-10. Even-denominator fractional quantum Hall states in the zeroth Landau level of ABA trilayer graphene. https://doi.org/10.1103/tsnc-4jjl

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