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arXiv · 2312.14767

Evidence for correlated electron pairs and triplets in quantum Hall interferometers

Wenmin Yang·David Perconte·Corentin Déprez·Kenji Watanabe·Takashi Taniguchi·Sylvain Dumont·Edouard Wagner·Frédéric Gay·Inès Safi·Hermann Sellier·Benjamin Sacépé
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Abstract

Pairing of electrons is ubiquitous in electronic systems featuring attractive inter-electron interactions, as exemplified in superconductors. Counter-intuitively, it can also be mediated in certain circumstances by the repulsive Coulomb interaction alone. Quantum Hall (QH) Fabry-P\'erot interferometers (FPIs) tailored in two-dimensional electron gas under a perpendicular magnetic field has been argued to exhibit such unusual electron pairing seemingly without attractive interaction. Here, we show evidence in graphene QH FPIs revealing not only a similar electron pairing at bulk filling factor nu=2 but also an unforeseen emergence of electron tripling characterized by a fractional Aharonov-Bohm flux period h/3e (h is the Planck constant and e the electron charge) at nu=3. Leveraging a novel plunger-gate spectroscopy, we demonstrate that electron pairing (tripling) involves correlated charge transport on two (three) entangled QH edge channels. This spectroscopy indicates a quantum interference flux-periodicity determined by the sum of the phases acquired by the distinct QH edge channels having slightly different interfering areas. While recent theory invokes the dynamical exchange of neutral magnetoplasmons -- dubbed neutralons -- as mediator for electron pairing, our discovery of three entangled QH edge channels with apparent electron tripling defies understanding and introduces a new three-body problem for interacting fermions.

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Wenmin Yang, David Perconte, Corentin Déprez, Kenji Watanabe, Takashi Taniguchi, Sylvain Dumont, Edouard Wagner, Frédéric Gay, Inès Safi, Hermann Sellier, Benjamin Sacépé. 2023-12-22. Evidence for correlated electron pairs and triplets in quantum Hall interferometers. https://doi.org/10.1038/s41467-024-54211-3

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