Electron-pairing in the quantum Hall regime due to neutralon exchange

TL;DR

This paper demonstrates that in quantum Hall Fabry-Pérot interferometers, electron pairing can occur due to neutralon exchange, leading to observable effects like enhanced shot noise, which advances understanding of electron interactions in topological systems.

Contribution

The paper provides a theoretical model showing electron pairing mediated by neutralon exchange in quantum Hall interferometers, explaining recent experimental observations.

Findings

Enhanced Fano factor indicating electron pairing

Electron pairing driven by neutralon exchange

Agreement with experimental shot noise data

Abstract

The behavior of electrons in condensed matter systems is mostly determined by the repulsive Coulomb interaction. However, under special circumstances the Coulomb interaction can be effectively attractive, giving rise to electron pairing in unconventional superconductors and specifically designed mesoscopic setups. In quantum Hall systems electron interactions can play a particularly important role due to the huge degeneracy of Landau levels, leading for instance to the emergence of quasi-particles with fractional charge and anyonic statistics. Quantum Hall Fabry-P\'erot (FPI) interferometers have attracted increasing attention due to their ability to probe such exotic physics. In addition, such interferometers are affected by electron interactions themselves in interesting ways. Recently, experimental evidence for electron pairing in a quantum Hall FPI was found (H.K. Choi et al., Nat. Comm 6, 7435 (2015)) . Theoretically describing an FPI in the limit of strong backscattering and under the influence of a screened Coulomb interaction, we compute electron shot noise and indeed find a two-fold enhanced Fano factor for some parameters, indicative of electron pairing. This result is explained in terms of an electron interaction due to exchange of neutral inter-edge plasmons, so-called neutralons.