Time-Resolved Detection of Individual Electrons in a Quantum Dot

TL;DR

This paper demonstrates real-time detection of individual electron tunneling events in a quantum dot using a nearby charge sensor, enabling quantitative analysis of quantum dot-reservoir coupling and occupation probabilities.

Contribution

It introduces a method for time-resolved measurement of single-electron dynamics in quantum dots with a quantum point contact as a charge detector.

Findings

Real-time observation of electron transfer events.

Quantitative extraction of quantum dot-reservoir coupling.

Determination of quantum dot state occupation probabilities.

Abstract

We present measurements on a quantum dot and a nearby, capacitively coupled, quantum point contact used as a charge detector. With the dot being weakly coupled to only a single reservoir, the transfer of individual electrons onto and off the dot can be observed in real time in the current signal from the quantum point contact. From these time-dependent traces, the quantum mechanical coupling between dot and reservoir can be extracted quantitatively. A similar analysis allows the determination of the occupation probability of the dot states.