Acoustic-phonon-assisted quantum control of qubit states near the Si/SiO2 interface

The waiting time between load/initialization and readout of electron spin qubit is related to electron tunneling between the donor and Si/SiO2 interface. Impacts of energy valley interference in silicon, lattice temperature, and screening of metallic gate on the waiting time associated with acoustic-phonon-assisted electron tunneling have been investigated. The results show that interface valley–orbit coupling causes its oscillation with donor depth and the influence of gate screening is significant when the SiO2 thickness is smaller than 10 nm. Moreover, the influences of these factors are strongest at critical electric field. -- Highlights: • Electron shuttling mediated by acoustic phonons for controlling electron spin qubits. • Energy valley interference, lattice temperature, and gate's screening effect. • Waiting time oscillates with donor depth due to interface valley-orbit coupling. • Gate's screening effect is significant when the SiO2 thickness is smaller than 10 nm. • The influences of all the factors are the strongest at critical electric field