Fractional Coulomb blockade for quasiparticle tunneling between edge channels

TL;DR

This study investigates fractional Coulomb blockade phenomena in a quantum dot within the fractional quantum Hall regime, revealing non-trivial edge state reconstructions and fractional charge tunneling, advancing understanding of anyonic quasiparticles.

Contribution

The paper introduces a model for charge stability and demonstrates fractional Coulomb blockade with fractional charge extraction in a quantum dot at fractional quantum Hall states.

Findings

Observation of magnetic field periodic modulation of Coulomb resonances.

Identification of fractional charge e*/e ≈ 0.32 in the quantum Hall regime.

Reconstruction of the quantum Hall edge states within the quantum dot.

Abstract

We study the magneto-conductance of a $1.4~\mathrm{\mu m}$-wide quantum dot in the fractional quantum Hall regime. For a filling factor $\approx 2/3$ and $\gtrsim 1/3$ in the quantum dot the observed Coulomb resonances show a periodic modulation in magnetic field. This indicates a non-trivial reconstruction of the 2/3 fractional quantum Hall state in the quantum dot. We present a model for the charge stability diagram of the system assuming two compressible regions separated by an incompressible stripe of filling factor $2/3$ and $1/3$, respectively. From the dependence of the magnetic field period on total magnetic field we construct the zero-field charge density distribution in the quantum dot. The tunneling between the two compressible regions exhibits fractional Coulomb blockade. For both filling factor regions, we extract a fractional charge $e^*/e = 0.32 \pm 0.03$ by comparing to measurements at filling factor 2. With their close relation to quantum Hall Fabry-P\'{e}rot interferometers, our investigations on quantum dots in the fractional quantum Hall regime extend and complement interference experiments investigating the nature of anyonic fractional quantum Hall quasiparticles.