Impact of the local valley splitting on the coherence of conveyor-belt spin shuttling in 28 Si/SiGe (opens in new tab)

Electron spins in silicon offer a promising path toward scalable, fault-tolerant quantum computing, with the potential to host millions of qubits. However, scaling up dense quantum-dot arrays and enabling qubit interconnections through shuttling are hindered by uncontrolled lateral variations of the valley splitting energy EVS. We map EVS across a 40 nm × 400 nm region of a 28Si/Si0.7Ge0.3 shuttle device and analyze the spin coherence of a single electron spin transported by conveyor-belt shu...