Radio frequency pulsed-gate charge spectroscopy on coupled quantum dots

TL;DR

This paper presents a radio frequency pulsed-gate technique for time-resolved charge spectroscopy in coupled quantum dots, enabling detection of electron dynamics on sub-nanosecond timescales and characterization of quantum dot properties.

Contribution

The study introduces a broadband radio frequency setup for pulsed-gate measurements, allowing detailed analysis of electron tunneling and relaxation in double quantum dots.

Findings

Detection of single-electron displacements below one nanosecond

Measurement of tunneling rates and relaxation times

Full characterization of tunable double quantum dots

Abstract

Time-resolved electron dynamics in coupled quantum dots is directly observed by a pulsed-gate technique. While individual gate voltages are modulated with periodic pulse trains, average charge occupations are measured with a nearby quantum point contact as detector. A key component of our setup is a sample holder optimized for broadband radio frequency applications. Our setup can detect displacements of single electrons on time scales well below a nanosecond. Tunneling rates through individual barriers and relaxation times are obtained by using a rate equation model. We demonstrate the full characterization of a tunable double quantum dot using this technique, which could also be used for coherent charge qubit control.