Single-Electron Effects in a Coupled Dot-Ring System

TL;DR

This paper investigates how single-electron screening affects Aharonov-Bohm oscillations in a coupled quantum ring-dot system, demonstrating potential for single-charge detection using quantum interference effects.

Contribution

It reveals that single-electron screening, not dephasing, causes the modulation of Aharonov-Bohm oscillations in a coupled quantum ring-dot system.

Findings

Aharonov-Bohm oscillation amplitude shows a minimum at dot conductance resonance.

Single-electron screening, not dephasing, explains the oscillation modulation.

Quantum ring oscillations can be used to detect single charges.

Abstract

Aharonov-Bohm oscillations are studied in the magnetoconductance of a micron-sized open quantum ring coupled capacitively to a Coulomb-blockaded quantum dot. As the plunger gate of the dot is modulated and tuned through a conductance resonance, the amplitude of the Aharonov-Bohm oscillations in the transconductance of the ring displays a minimum. We demonstrate that the effect is due to a single-electron screening effect, rather than to dephasing. Aharonov-Bohm oscillations in a quantum ring can thus be used for the detection of single charges.