A two-dimensional array of single-hole quantum dots

TL;DR

This paper demonstrates a scalable two-dimensional array of germanium quantum dots with single-charge control, advancing quantum information processing capabilities.

Contribution

It introduces a two-dimensional quantum dot array with integrated charge sensors, enabling precise tuning and coupling control in germanium-based quantum dots.

Findings

Achieved single-hole occupancy in a 2D array

Controlled coupling from isolated to exchange-coupled dots

Verified charge filling with Fock-Darwin spectrum

Abstract

Quantum dots fabricated using techniques and materials that are compatible with semiconductor manufacturing are promising for quantum information processing. While great progress has been made toward high-fidelity control of quantum dots positioned in a linear arrangement, scalability along two dimensions is a key step toward practical quantum information processing. Here we demonstrate a two-dimensional quantum dot array where each quantum dot is tuned to single-charge occupancy, verified by simultaneous measuring with two integrated radio frequency charge sensors. We achieve this by using planar germanium quantum dots with low disorder and small effective mass, allowing the incorporation of dedicated barrier gates to control the coupling of the quantum dots. We demonstrate hole charge filling consistent with a Fock-Darwin spectrum and show that we can tune single-hole quantum dots from isolated quantum dots to strongly exchange coupled quantum dots. These results motivate the use of planar germanium quantum dots as building blocks for quantum simulation and computation.