Spatial mapping and manipulation of two tunnel-coupled quantum dots

TL;DR

This paper demonstrates spatially resolved control and imaging of tunnel-coupled quantum dots using a scanning force microscope at ultra-low temperatures, revealing their positions and state-dependent shifts.

Contribution

It introduces a method for spatial mapping and manipulation of quantum dots with high resolution, enabling detailed investigation of their spatial and electronic properties.

Findings

Quantum dots' positions are spatially resolved.

Quantum states influence apparent relative shifts.

Scanning gate techniques effectively image quantum dot behavior.

Abstract

The metallic tip of a scanning force microscope operated at 300 mK is used to locally induce a potential in a fully controllable double quantum dot defined via local anodic oxidation in a GaAs/AlGaAs heterostructure. Using scanning gate techniques we record spatial images of the current through the sample for different numbers of electrons on the quantum dots (i.e., for different quantum states). Owing to the spatial resolution of current maps, we are able to determine the spatial position of the individual quantum dots, and investigate their apparent relative shifts due to the voltage applied to a single gate.