Probing microwave capacitance of self-assembled quantum dots

TL;DR

This paper introduces a microwave capacitance sensing technique for self-assembled quantum dots, enabling rapid, local detection of charge and spin states with high sensitivity, advancing quantum information research.

Contribution

The authors develop a microwave microstrip resonator sensor capable of detecting single-electron capacitance in quantum dots, integrated into a scanning microscope for detailed quantum state analysis.

Findings

Capacitance sensitivity of ~10^(-19) F/√Hz achieved.

Potential for probing single charge and spin dynamics.

Integration into scanning microscopy enhances quantum dot characterization.

Abstract

Self-assembled quantum dots have remarkable optical, electronic and spintronic properties that make them leading candidates for quantum information technologies. Their characterization requires rapid and local determination of both charge and spin degrees of freedom. We present a way to probe the capacitance of small ensembles of quantum dots at microwave frequencies. The technique employs a capacitance sensor based on a microwave microstrip resonator with sensitivity ~10^(-19) F/rt(Hz), high enough to probe single electrons. The integration of this design in a scanning microscope will provide an important tool for investigating single charge and spin dynamics in self-assembled quantum dot systems.