1/2 Fractional Quantum Hall State in a GaAs 2D Hole System at a Landau Level Crossing: Observation of ν = 7/13 and 9/19 Daughter States
ORAL
Abstract
The strong spin-orbit coupling in GaAs two-dimensional hole systems (2DHSs) leads to a complex Landau level (LL) spectrum, giving rise to a novel even-denominator fractional quantum Hall state (FQHS) at ½ stemming from a LL crossing [1]. Here we report a robust, crossing ½ FQHS in a 2DHS confined to a 25-nm-wide GaAs quantum well when the two lowest LL (orbital number, N = 0) cross near . When the charge distribution is tuned to be slightly asymmetric, a pair of daughter states appear at and , manifested by anomalously deep minima in Rxx and well-developed plateaus in Rxy. We further studied the evolution of the daughter states as a function of carrier density, charge imbalance, and in-plane magnetic field. We found that the daughter states remain strong only when there is a certain amount of imbalance and in the proximity to the LL crossing. The and 9/19 pair of daughter states we observe match the theoretical prediction for a 1/2 FQHS [2,3], suggesting a two-component origin for the crossing 1/2 FQHS, with the two crossing LLs serving as the pseudo-spin components. This is in contrast to the recent studies in 2D electron systems confined to wide GaAs quantum wells [4], where the pair of daughter states observed are at and 8/17, consistent with a Pfaffian origin for the 1/2 FQHS in those systems.
References:
[1] Y. Liu et al., Even-denominator fractional quantum Hall effect at a Landau level crossing, Phys.
Rev. B 89, 165313 (2014).
[2] M. Levin and B.I. Halperin, Collective states of non-Abelian quasiparticles in a magnetic field, Phys Rev. B 79, 205301 (2009).
[3] M. Yutushui et al., Paired fermions in strong magnetic fields and daughters of even-denominator Hall plateaus, Phys Rev. B 110, 165402 (2024).
[4] S. Singh et al., Topological phase transition between Jain states and daughter states of the
= 1/2 fractional quantum Hall state, Nat. Phys. 20, 1247 (2024).
References:
[1] Y. Liu et al., Even-denominator fractional quantum Hall effect at a Landau level crossing, Phys.
Rev. B 89, 165313 (2014).
[2] M. Levin and B.I. Halperin, Collective states of non-Abelian quasiparticles in a magnetic field, Phys Rev. B 79, 205301 (2009).
[3] M. Yutushui et al., Paired fermions in strong magnetic fields and daughters of even-denominator Hall plateaus, Phys Rev. B 110, 165402 (2024).
[4] S. Singh et al., Topological phase transition between Jain states and daughter states of the
= 1/2 fractional quantum Hall state, Nat. Phys. 20, 1247 (2024).
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Presenters
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Chia-Tse Tai
- Princeton University