  We present how optical coherent population trapping (CPT) of the spin of
localized semiconductor electrons stabilizes the surrounding nuclear spin bath
via the hyperfine interaction, resulting in a state which is more ordered than
the thermal equilibrium state. We find distinct control regimes for different
signs of laser detuning and examine the transition from an unpolarized,
narrowed state to a polarized state possessing a bistability. The narrowing of
the state yields slower electron spin dephasing and self-improving CPT. Our
analysis is relevant for a variety of solid state systems where
hyperfine-induced dephasing is a limitation for using electron spin coherence.
