All-electrical manipulation of silicon spin qubits with tunable spin-valley mixing

Silicon qubits can show a strong interplay between spin and valley physics. The spin is much more robust to decoherence than the valley degree of freedom, but is more difficult to address electrically. Here, the authors show via atomistic simulations that a spin qubit can be continuously transformed into a valley qubit for manipulation, then brought back to the spin regime to benefit from the longer lifetimes. This transformation relies on intrinsic spin-orbit coupling and suitable engineering of the electric field in the device. This opens up new possibilities for the design of robust and electrically addressable silicon qubits.