  Several systems in the solid state have been suggested as promising
candidates for spin-based quantum information processing. In spite of
significant progress during the last decade, there is a search for new systems
with higher potential [D. DiVincenzo, Nature Mat. 9, 468 (2010)]. We report
that silicon vacancy defects in silicon carbide comprise the technological
advantages of semiconductor quantum dots and the unique spin properties of the
nitrogen-vacancy defects in diamond. Similar to atoms, the silicon vacancy
qubits can be controlled under the double radio-optical resonance conditions,
allowing for their selective addressing and manipulation. Furthermore, we
reveal their long spin memory using pulsed magnetic resonance technique. All
these results make silicon vacancy defects in silicon carbide very attractive
for quantum applications.
