Valley splitting of single-electron Si MOS quantum dots

TL;DR

This paper presents experimental data and a theory that accurately predict and control valley splitting in silicon MOS quantum dots, advancing their potential as reliable qubits by addressing a key challenge in silicon quantum computing.

Contribution

It introduces a new experiment and a quantitative theory that predict valley splitting in silicon quantum dots, demonstrating control over this critical parameter.

Findings

Valley physics is consistent across different fabrication processes.

The developed theory matches experimental data quantitatively.

Valley splitting can be deterministically predicted and controlled.

Abstract

Silicon-based metal-oxide-semiconductor quantum dots are prominent candidates for high-fidelity, manufacturable qubits. Due to silicon's band structure, additional low-energy states persist in these devices, presenting both challenges and opportunities. Although the physics governing these valley states has been the subject of intense study, quantitative agreement between experiment and theory remains elusive. Here, we present data from a new experiment probing the valley states of quantum dot devices and develop a theory that is in quantitative agreement with both the new experiment and a recently reported one. Through sampling millions of realistic cases of interface roughness, our method provides evidence that, despite radically different processing, the valley physics between the two samples is essentially the same. This work provides the first evidence that valley splitting can be deterministically predicted and controlled in metal oxide semiconductor quantum dots, a critical requirement for such systems to realize a reliable qubit platform.