  Compared to electrons, holes in InAs quantum dots have a significantly weaker
hyperfine interaction that leads to less dephasing from nuclear spins. Thus
many recent studies have suggested that nuclear spins are unimportant for hole
spin dynamics compared to electric field fluctuations. We show that the hole
hyperfine interaction can have a strong effect on hole spin coherence
measurements through a nuclear feedback effect. The nuclear polarization is
generated through a unique process that is dependent on the anisotropy of the
hole hyperfine interaction and the coherent precession of nuclear spins, giving
rise to strong modulation at the nuclear precession frequency.
