  We demonstrate the coherent control and electrical readout of the nuclear
spins of ionized phosphorus donors in natural silicon. By combining pulsed
illumination with coherent electron spin manipulation, we selectively ionize
the donor depending on its nuclear spin state, exploiting a spin-dependent
recombination process via a spin pair at the Si/SiO2 interface. The
nuclear-spin coherence time of the ionized donor is 18 ms, two orders of
magnitude longer than in the neutral donor state, rendering the ionized donor a
potential resource as a quantum memory. The presented experimental techniques
allow for spectroscopy of ionized-donor nuclear spins, increase the sensitivity
of electrically detected electron nuclear double resonance by more than two
orders of magnitude, and give experimental access to the lifetime of parallel
electron spin pairs.
