Spatially resolved manipulation of single electrons in quantum dots using a scanned probe

TL;DR

This paper demonstrates spatial control and imaging of single electrons in quantum dots using a scanned metallic tip, revealing detailed interaction potentials at very low temperatures.

Contribution

It introduces a method for manipulating and imaging single electrons in quantum dots with a scanned probe, providing new insights into tip-dot interactions.

Findings

Single electrons can be moved on or off the quantum dot via tip movement or bias voltage.

Spatial conductance images reveal the interaction potential between the tip and quantum dot states.

The interaction potential includes both tip-voltage dependent and independent components.

Abstract

The scanning metallic tip of a scanning force microscope was coupled capacitively to electrons confined in a lithographically defined gate-tunable quantum dot at a temperature of 300 mK. Single electrons were made to hop on or off the dot by moving the tip or by changing the tip bias voltage owing to the Coulomb-blockade effect. Spatial images of conductance resonances map the interaction potential between the tip and individual electronic quantum dot states. Under certain conditions this interaction is found to contain a tip-voltage induced and a tip-voltage independent contribution.