Interferometry reveals spin-singlet fractional quantum Hall edges in graphene
Abstract
The edge modes of spin-singlet fractional quantum Hall (FQH) phases are manifestations of multicomponent topological order and SU(2) spin symmetry. An archetype is the spin-unpolarized state at ν=2/3, whose edge is expected to host spatially coexisting yet counter-propagating charge and neutral spin modes. Despite efforts, its edge properties, including spin coherence and spin-charge separation, have remained elusive owing to the difficulty of resolving spins in FQH edge transport. Here, we develop a spin-sensitive probe of graphene FQH edges by using a p-n junction to interface a target FQH state with a probe integer quantum Hall (QH) state of opposite polarity. An Aharonov-Bohm (AB) interferometer forms along the interface, when the target and probe edge channels carry the same spin. We identify the spin-unpolarized and polarized edges of the ν=2/3 states at lower and higher magnetic fields, respectively, through spin-dependent interference. A novel multiparticle AB interference between two electrons of opposite spin emerges from spin-charge separation and recombination on the unpolarized edge, featuring a spin swap. Our results establish edge transport as a probe of spin-singlet topological orders, with implications for parafermion platforms in graphene-superconductor hybrids.
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BibTeX
@misc{ayache2026interferometry,
title = {{Interferometry reveals spin-singlet fractional quantum Hall edges in graphene}},
author = {R. Ayache and K. Kim and M. Kuiri and Q. Benichou and H. Chakraborti and L. Pugliese and K. Watanabe and T. Taniguchi and H. -S. Sim and P. Roulleau},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.01233},
eprint = {2609.01233},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.01233},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Interferometry reveals spin-singlet fractional quantum Hall edges in graphene
AU - R. Ayache
AU - K. Kim
AU - M. Kuiri
AU - Q. Benichou
AU - H. Chakraborti
AU - L. Pugliese
AU - K. Watanabe
AU - T. Taniguchi
AU - H. -S. Sim
AU - P. Roulleau
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.01233
UR - https://arxiv.org/abs/2609.01233
AB - The edge modes of spin-singlet fractional quantum Hall (FQH) phases are manifestations of multicomponent topological order and SU(2) spin symmetry. An archetype is the spin-unpolarized state at ν=2/3, whose edge is expected to host spatially coexisting yet counter-propagating charge and neutral spin modes. Despite efforts, its edge properties, including spin coherence and spin-charge separation, have remained elusive owing to the difficulty of resolving spins in FQH edge transport. Here, we develop a spin-sensitive probe of graphene FQH edges by using a p-n junction to interface a target FQH state with a probe integer quantum Hall (QH) state of opposite polarity. An Aharonov-Bohm (AB) interferometer forms along the interface, when the target and probe edge channels carry the same spin. We identify the spin-unpolarized and polarized edges of the ν=2/3 states at lower and higher magnetic fields, respectively, through spin-dependent interference. A novel multiparticle AB interference between two electrons of opposite spin emerges from spin-charge separation and recombination on the unpolarized edge, featuring a spin swap. Our results establish edge transport as a probe of spin-singlet topological orders, with implications for parafermion platforms in graphene-superconductor hybrids.
ER -