  The electronic and nuclear spin degrees of freedom for donor impurities in
semiconductors form ultra coherent two-level systems that are useful for
quantum information applications. Spins naturally have magnetic dipoles, so
alternating current (AC) magnetic fields are frequently used to drive spin
transitions and perform quantum gates. These fields can be difficult to
spatially confine to single donor qubits so alternative methods of control such
as AC electric field driven spin resonance are desirable. However, donor spin
qubits do not have electric dipole moments so that they can not normally be
driven by electric fields. In this work we challenge that notion by
demonstrating a new, all-electric-field method for controlling neutral $^{31}$P
and $^{75}$As donor nuclear spins in silicon through modulation of their
donor-bound electrons. This method has major advantages over magnetic field
control since electric fields are easy to confine at the nanoscale. This leads
to lower power requirements, higher qubit densities, and faster gate times. We
also show that this form of control allows for driving nuclear spin qubits at
either their resonance frequency or the first subharmonic of that frequency,
thus reducing device bandwidth requirements. Interestingly, as we relax the
bandwidth requirements, we demonstrate that the computational Hilbert space is
expanded to include double quantum transitions, making it feasible to use all
four nuclear spin states to implement nuclear-spin-based qudits in Si:As. Based
on these results, one can envision novel high-density, low-power quantum
computing architectures using nuclear spins in silicon.
