Local self-organization of islands in embedded nanodot systems...

We show that strain distribution on the surface of an isotropic spacer layer induced by an embedded
island of large base-to-height aspect ratio deviates significantly from the description of the point
force dipole model in the regime of small spacer layer thickness. In this regime, the strain profile
displays several local maxima above the embedded island. The regions with local strain maxima
serve as nucleation centers for growth of surface islands under appropriate growth conditions,
resulting in locally well-organized surface islands above the embedded island. Our theoretical
results are in excellent agreement with recent experiments for Ge islands embedded in Si.