Baseband control of single-electron silicon spin qubits in two dimensions
- Florian K. Unseld
- Brennan Undseth
- Eline Raymenants
- Yuta Matsumoto
- Sander L. de Snoo
- Saurabh Karwal
- Oriol Pietx-Casas
- Alexander S. Ivlev
- Marcel Meyer
- Amir Sammak
- Menno Veldhorst
- Giordano Scappucci
- Lieven M. K. Vandersypen
2025-07-01
Micromagnet-enabled electric-dipole spin resonance (EDSR) is an established method for high-fidelity single-spin control in silicon, although so far experiments have been restricted to one-dimensional arrays. In contrast, qubit control based on hopping spins has recently emerged as a compelling alternative, with high-fidelity baseband control realized in sparse two-dimensional hole arrays in germanium. In this work, we commission a 28 Si/SiGe 2 × 2 quantum dot array both as a four-qubit device using EDSR and as a two-qubit device using baseband hopping control. We establish a lower bound on the fidelity of the hopping gate of 99.50(6)%, which is similar to the average fidelity of the resonant gate. The hopping gate also circumvents the transient pulse-induced resonance shift from heating observed during EDSR operation. To motivate hopping spins as an attractive means of scaling silicon spin-qubit arrays, we propose an extensible nanomagnet design that enables engineered baseband control of large spin arrays.