Measurement of Enhanced Spin-Orbit Coupling Strength for Donor-Bound Electron Spins in Silicon

Adv Mater. 2024 Dec;36(49):e2405916. doi: 10.1002/adma.202405916. Epub 2024 Oct 15.

Abstract

While traditionally considered a deleterious effect in quantum dot spin qubits, the spin-orbit interaction is recently being revisited as it allows for rapid coherent control by on-chip AC electric fields. For electrons in bulk silicon, spin-orbit coupling (SOC) is intrinsically weak, however, it can be enhanced at surfaces and interfaces, or through atomic placement. Here it is showed that the strength of the spin-orbit coupling can be locally enhanced by more than two orders of magnitude in the manybody wave functions of multi-donor quantum dots compared to a single donor, reaching strengths so far only reported for holes or two-donor system with certain symmetry. These findings may provide a pathway toward all-electrical control of donor-bound spins in silicon using electric dipole spin resonance (EDSR).

Keywords: electric dipole spin resonance (EDSR); quantum dots; silicon; spin qubits; spin‐orbit coupling (SOC).