  Geometric phase analysis has been applied to high resolution aberration
corrected (scanning) transmission electron microscopy images of InAs/GaAs
quantum dot (QD) materials. We show quantitatively how the lattice mismatch
induced strain varies on the atomic scale and tetragonally distorts the lattice
in a wide region that extends several nanometers into the GaAs spacer layer
below and above the QDs. Finally, we show how V-shaped dislocations originating
at the QD/GaAs interface efficiently remove most of the lattice mismatch
induced tetragonal distortions in and around the QD.
