Probing low noise at the MOS interface with a spin-orbit qubit

TL;DR

This paper introduces a silicon spin-orbit qubit that achieves all-electrical two-axis control without additional components, maintains low noise at the MOS interface, and demonstrates promising coherence times for quantum computing applications.

Contribution

The study demonstrates a novel silicon spin-orbit qubit with intrinsic two-axis control and low noise, eliminating the need for non-ideal control components and leveraging the MOS interface's properties.

Findings

Achieved all-electrical two-axis control of silicon qubits.

Demonstrated charge noise properties comparable to other semiconductor systems.

Measured spin dephasing times of 1.6 microseconds with isotopically enriched silicon.

Abstract

The silicon metal-oxide-semiconductor (MOS) material system is technologically important for the implementation of electron spin-based quantum information technologies. Researchers predict the need for an integrated platform in order to implement useful computation, and decades of advancements in silicon microelectronics fabrication lends itself to this challenge. However, fundamental concerns have been raised about the MOS interface (e.g. trap noise, variations in electron g-factor and practical implementation of multi-QDs). Furthermore, two-axis control of silicon qubits has, to date, required the integration of non-ideal components (e.g. microwave strip-lines, micro-magnets, triple quantum dots, or introduction of donor atoms). In this paper, we introduce a spin-orbit (SO) driven singlet-triplet (ST) qubit in silicon, demonstrating all-electrical two-axis control that requires no additional integrated elements and exhibits charge noise properties equivalent to other more model, but less commercially mature, semiconductor systems. We demonstrate the ability to tune an intrinsic spin-orbit interface effect, which is consistent with Rashba and Dresselhaus contributions that are remarkably strong for a low spin-orbit material such as silicon. The qubit maintains the advantages of using isotopically enriched silicon for producing a quiet magnetic environment, measuring spin dephasing times of 1.6 $\mu$s using 99.95% $^{28}$Si epitaxy for the qubit, comparable to results from other isotopically enhanced silicon ST qubit systems. This work, therefore, demonstrates that the interface inherently provides properties for two-axis control, and the technologically important MOS interface does not add additional detrimental qubit noise.