An electrostatically defined serial triple quantum dot charged with few electrons

TL;DR

This paper demonstrates control and characterization of a triple quantum dot system in GaAs/AlGaAs, revealing charge configurations, tunneling conductance, and quantum cellular automata processes through experimental and modeling approaches.

Contribution

It introduces an electrostatic model for charge configurations and compares numerical calculations with experimental data in a triple quantum dot system.

Findings

Control over few-electron charge states demonstrated

Charge reconfiguration via quantum cellular automata observed

Model and experiment show consistent ground state configurations

Abstract

A serial triple quantum dot (TQD) electrostatically defined in a GaAs/AlGaAs heterostructure is characterized by using a nearby quantum point contact as charge detector. Ground state stability diagrams demonstrate control in the regime of few electrons charging the TQD. An electrostatic model is developed to determine the ground state charge configurations of the TQD. Numerical calculations are compared with experimental results. In addition, the tunneling conductance through all three quantum dots in series is studied. Quantum cellular automata processes are identified, which are where charge reconfiguration between two dots occurs in response to the addition of an electron in the third dot.