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arXiv · 2309.00111

Topological phase transition between composite-fermion and Pfaffian daughter states near {\nu} = 1/2 FQHS

Siddharth Kumar Singh·C. Wang·C. T. Tai·C. S. Calhoun·A. Gupta·K. W. Baldwin·L. N. Pfeiffer·M. Shayegan
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Abstract

$\nu$=1/2 is among the most enigmatic many-body phases in two-dimensional electron systems as it appears in the ground-state rather than an excited Landau level. It is observed in wide quantum wells where the electrons have a bilayer charge distribution with finite tunneling. Whether this 1/2 FQHS is two-component (Abelian) or one-component (non-Abelian) has been debated since its experimental discovery over 30 years ago. Here, we report strong 1/2 FQHSs in ultrahigh-quality, wide, GaAs quantum wells, with transport energy gaps up to $\simeq$4K, among the largest gaps reported for any even-denominator FQHS. The 1/2 FQHS is flanked by numerous, Jain-sequence FQHSs at $\nu$=$p$/(2$p$$\pm$1) up to $\nu$=8/17 and 9/17. Remarkably, as we raise the density and strengthen the 1/2 FQHS, the 8/17 and 7/13 FQHSs suddenly become strong, much stronger than their neighboring high-order FQHSs. Insofar as FQHSs at $\nu$=8/17 and 7/13 are precisely the theoretically-predicted, simplest, daughter states of the one-component Pfaffian 1/2 FQHS, our data suggest a topological phase-transition of 8/17 and 7/13 FQHSs from the Jain-states to the daughter states of the Pfaffian, and that the parent 1/2 FQHS we observe is the Pfaffian state.

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Siddharth Kumar Singh, C. Wang, C. T. Tai, C. S. Calhoun, A. Gupta, K. W. Baldwin, L. N. Pfeiffer, M. Shayegan. 2023-08-31. Topological phase transition between composite-fermion and Pfaffian daughter states near {\nu} = 1/2 FQHS. https://doi.org/10.1038/s41567-024-02517-w

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