Differential Charge Sensing and Charge Delocalization in a Tunable Double Quantum Dot

TL;DR

This paper demonstrates a tunable double quantum dot with integrated charge sensors, enabling detailed charge distribution measurements and insights into charge delocalization, tunnel coupling, and temperature effects in the quantum regime.

Contribution

It introduces a novel charge sensing method that accurately measures charge distribution and tunnel coupling without relying on transport measurements.

Findings

Charge distribution within the double dot can be spatially resolved.

Charge delocalization varies with temperature and tunnel coupling.

Local charge sensing accurately determines interdot tunnel coupling.

Abstract

We report measurements of a tunable double quantum dot, operating in the quantum regime, with integrated local charge sensors. The spatial resolution of the sensors is sufficient to allow the charge distribution within the double dot system to be resolved at fixed total charge. We use this readout scheme to investigate charge delocalization as a function of temperature and strength of tunnel coupling, showing that local charge sensing allows an accurate determination of interdot tunnel coupling in the absence of transport.