  We demonstrate the optical initialization of a hole-spin qubit bound to an
isoelectronic center (IC) formed by a pair of Te impurities in ZnSe, an
impurity/host system providing high optical homogeneity, large electric dipole
moments, and long coherence times. The initialization scheme is based on the
spin-preserving tunneling of a resonantly excited donor-bound exciton to a
positively charged Te IC, thus forming a positive trion. The radiative decay of
the trion within less than 50 ps leaves a heavy hole in a well-defined
polarization-controlled spin state. The initialization fidelity exceeds 98:5 %
for an initialization time of less than 150 ps.
