  We investigate how the strain-induced nuclear quadrupole interaction
influences the degree of nuclear spin polarization in self-assembled quantum
dots. Our calculation shows that the achievable nuclear spin polarization in
In_{x}Ga_{1-x}As quantum dots is related to the concentration of indium and the
resulting strain distribution in the dots. The interplay between the nuclear
quadrupole interaction and Zeeman splitting leads to interesting features in
the magnetic field dependence of the nuclear spin polarization. Our results are
in qualitative agreement with measured nuclear spin polarization by various
experimental groups.
