Ryan M. Jock

A silicon metal-oxide-semiconductor electron spin-orbit qubit

The silicon metal-oxide-semiconductor (MOS) material system is a technologically important implementation of spin-based quantum information processing. However, the MOS interface is imperfect leading to concerns about 1/f trap noise and variability in the electron g-factor due to spin–orbit (SO) effects. Here we advantageously use interface–SO coupling for a critical control axis in a double-quantum-dot singlet–triplet qubit. The magnetic field-orientation dependence of the g-factors is consistent with Rashba and Dresselhaus interface–SO contributions. The resulting all-electrical, two-axis control is also used to probe the MOS interface noise. The measured inhomogeneous dephasing time,

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

T_{{\mathrm{2m}}}^ \star

Implications of the Spin-Orbit Effect for Singlet-Triplet Qubit Operation

T2m⋆, of 1.6 μs is consistent with 99.95% 28Si enrichment. Furthermore, when tuned to be sensitive to exchange fluctuations, a quasi-static charge noise detuning variance of 2 μeV is observed, competitive with low-noise reports in other semiconductor qubits. This work, therefore, demonstrates that the MOS interface inherently provides properties for two-axis qubit control, while not increasing noise relative to other material choices.As the performance of silicon-based qubits has improved, there has been increasing focus on developing designs that are compatible with industrial processes. Here, Jock et al. exploit spin-orbit coupling to demonstrate full, all-electrical control of a metal-oxide-semiconductor electron spin qubit.Ryan M. Jock, ∗ N. Tobias Jacobson, Patrick Harvey-Collard, 3 Andrew M. Mounce, Vanita Srinivasa, Dan R. Ward, John Anderson, Ron Manginell, Joel R. Wendt, Martin Rudolph, Tammy Pluym, John King Gamble, Andrew D. Baczewski, Wayne M. Witzel, and Malcolm S. Carroll † Sandia National Laboratories, Albuquerque, NM 87185, USA Center for Computing Research, Sandia National Laboratories, Albuquerque, NM 87185, USA Département de physique et Institut quantique, Université de Sherbrooke, 2500 boul. de l’Université, Sherbrooke, QC, J1K 2R1, Canada

Single-Shot Readout of a S/T Qubit with a Cryogenic AC-Coupled HBT Amplifier in a Lithographic MOS Double Quantum Dot

Si-MOS based QD qubits are attractive due to their similarity to the current semiconductor industry. We introduce a highly tunable MOS foundry compatible qubit design that couples an electrostatic quantum dot (QD) with an implanted donor. We show for the first time coherent two-axis control of a two-electron spin logical qubit that evolves under the QD-donor exchange interaction and the hyperfine interaction with the donor nucleus. The two interactions are tuned electrically with surface gate voltages to provide control of both qubit axes. Qubit decoherence is influenced by charge noise, which is of similar strength as epitaxial systems like GaAs and Si/SiGe.