Coulomb Blockade in an Open Quantum Dot

TL;DR

This paper reports the observation of Coulomb blockade effects in an open quantum dot system with fully transmitting contacts, revealing residual charge quantization due to mesoscopic electron interference at very low temperatures.

Contribution

It demonstrates Coulomb blockade phenomena in an open quantum dot system, challenging the prior assumption that such systems are free of Coulomb interactions.

Findings

Periodic conductance oscillations with gate voltage at low temperatures.

Evidence of residual charge quantization in an open quantum dot.

Identification of mesoscopic Coulomb blockade caused by electron interference.

Abstract

We report the observation of Coulomb blockade in a quantum dot contacted by two quantum point contacts each with a single fully-transmitting mode, a system previously thought to be well described without invoking Coulomb interactions. At temperatures below 50 mK we observe a periodic oscillation in the conductance of the dot with gate voltage that corresponds to a residual quantization of charge. From the temperature and magnetic field dependence, we infer the oscillations are Mesoscopic Coulomb Blockade, a type of Coulomb blockade caused by electron interference in an otherwise open system.