Detection of Coulomb Charging around an Antidot

TL;DR

This paper reports the detection of Coulomb charging oscillations around an antidot in a 2D electron gas, revealing a new Coulomb blockade phenomenon and evidence of spin state coupling in magnetic fields.

Contribution

It introduces a novel Coulomb blockade effect around an antidot and explores spin coupling, expanding understanding of electron interactions in quantum Hall systems.

Findings

Observation of charge oscillations as a function of magnetic field.

Evidence for coupling between opposite spin states.

Detection of h/2e oscillations indicating quantum coherence.

Abstract

We have detected oscillations of the charge around a potential hill (antidot) in a two-dimensional electron gas as a function of a perpendicular magnetic field B. The field confines electrons around the antidot in closed orbits, the areas of which are quantised through the Aharonov-Bohm effect. Increasing B reduces each state's area, pushing electrons closer to the centre, until enough charge builds up for an electron to tunnel out. This is a new form of the Coulomb blockade seen in electrostatically confined dots. We have also studied h/2e oscillations and found evidence for coupling of opposite spin states of the lowest Landau level.