A 2x2 quantum dot array in silicon with fully tuneable pairwise interdot coupling

TL;DR

This paper demonstrates a silicon-based 2D quantum dot array with fully tunable pairwise interdot coupling, advancing the development of scalable quantum processors compatible with existing manufacturing techniques.

Contribution

The work introduces a silicon MOS quantum dot array with controllable interdot exchange interactions in two dimensions, a key step toward scalable quantum computing architectures.

Findings

Achieved control of all nearest-neighbor tunnel couplings up to 30 decades per volt.

Demonstrated formation and isolation of double-dot and triple-dot configurations at 4.2 K.

Used modeling to estimate exchange interactions among qubits in the array.

Abstract

Recent advances in semiconductor spin qubits have achieved linear arrays exceeding ten qubits. Moving to two-dimensional (2D) qubit arrays is a critical next step to advance towards fault-tolerant implementations, but it poses substantial fabrication challenges, particularly because enabling control of nearest-neighbor entanglement requires the incorporation of interstitial exchange gates between quantum dots in the qubit architecture. In this work, we present a 2D array of silicon metal-oxide-semiconductor (MOS) quantum dots with tunable interdot coupling between all adjacent dots. The device is characterized at 4.2 K, where we demonstrate the formation and isolation of double-dot and triple-dot configurations. We show control of all nearest-neighbor tunnel couplings spanning up to 30 decades per volt through the interstitial exchange gates and use advanced modeling tools to estimate the exchange interactions that could be realized among qubits in this architecture. These results represent a significant step towards the development of 2D MOS quantum processors compatible with foundry manufacturing techniques.