  The elimination of defects from SiC has facilitated its move to the forefront
of the optoelectronics and power-electronics industries. Nonetheless, because
the electronic states of SiC defects can have sharp optical and spin
transitions, they are increasingly recognized as a valuable resource for
quantum-information and nanoscale-sensing applications. Here, we show that
individual electron spin states in highly purified monocrystalline 4H-SiC can
be isolated and coherently controlled. Bound to neutral divacancy defects,
these states exhibit exceptionally long ensemble Hahn-echo spin coherence,
exceeding 1 ms. Coherent control of single spins in a material amenable to
advanced growth and microfabrication techniques is an exciting route to
wafer-scale quantum technologies.
