Nanotechnology Now - Press Release: CEA-Leti and Partners Demo Potentially Scalable Readout System for Large Arrays of Quantum Dots: Results Hold promise for Fast, Accurate Single-Shot Readout �Of Foundry-Compatible Si MOS Spin Qubits�

In a paper presented at IEDM 2019, the international research team reported its work on developing a toolkit on a SOI MOSFET-based prototyping platform that enables fast reading of the states of charge and spin. The study explored two gate-based reflectometry readout systems for probing charge and spin states in linear arrangements of MOS split-gate-defined arrays of quantum dots. The first system gives the exact number of charges entering the array and can help to initialize it. It can also read spin states, albeit in relatively small arrays. The second one gives the spin state in any quantum dot regardless of the array length, but is not useful for tracking charge number. Both readout schemes can be used complementarily in large arrays.

The study�s findings �bear significance for fast, high-fidelity, single-shot readout of large arrays of foundry-compatible Si MOS spin qubits,� the paper notes.

�The short-term efforts for our team going forward will be a joint optimization to increase speed and reliability of the readouts,� said CEA-Leti�s Louis Hutin, lead author on the paper. �The longer-term goal is to transfer this know-how on a larger scale and to less conventional architectures, featuring an optimized topology for error correction.�

Reflectometry is a technique that leverages signal reflections along a conducting line when an incident RF wave meets an impedance discontinuity. In CEA-Leti�s study, the probing line was connected to the MOS gate of a Si quantum dot. The system was prepared so that the load impedance depends on the spin state of the qubit, which enabled the team to monitor single spin events non-destructively and almost as they occurred.

In addition to CEA-Leti, the research team includes CNRS Institut N�el and CEA-IRIG, Grenoble, France; the Niels Bohr Institute, University of Copenhagen, Denmark; and Hitachi Cambridge Laboratory and Cavendish Laboratory, University of Cambridge, UK. Their paper is titled �Gate Reflectometry for Probing Charge and Spin States in Linear Si MOS Split-Gate Arrays�.

About CEA-LetiLeti, a technology research institute at CEA Tech, is a global leader in miniaturization technologies enabling smart, energy-efficient and secure solutions for industry. Founded in 1967, Leti pioneers micro-& nanotechnologies, tailoring differentiating applicative solutions for global companies, SMEs and startups. Leti tackles critical challenges in healthcare, energy and digital migration. From sensors to data processing and computing solutions, Leti�s multidisciplinary teams deliver solid expertise, leveraging world-class pre-industrialization facilities. With a staff of more than 1,900, a portfolio of 2,700 patents, 91,500 sq. ft. of cleanroom space and a clear IP policy, the institute is based in Grenoble, France, and has offices in Silicon Valley and Tokyo. Leti has launched 60 startups and is a member of the Carnot Institutes network. Follow us on www.leti-cea.com and @CEA_Leti.Follow us on www.leti.fr/en and @CEA_Leti.

CEA Tech is the technology research branch of the French Alternative Energies and Atomic Energy Commission (CEA), a key player in innovative R&D, defence & security, nuclear energy, technological research for industry and fundamental science, identified by Thomson Reuters as the second most innovative research organization in the world. CEA Tech leverages a unique innovation-driven culture and unrivalled expertise to develop and disseminate new technologies for industry, helping to create high-end products and provide a competitive edge.