jMol series nanotwin ends

Here's a model of the {112} plane termination of a {111} nanotwin in silicon, as viewed initially down a <110> direction shared by twins to both left and right. A {111} twin plane by itself is illustrated here, and a nanotwin (set of paired twin planes) internally terminated on a {112} plane is illustrated here. This model focusses on atom positions just at the termination.

In the model below, atoms which have too many near neighbors (more than 4) are colored red, while those with too few near neighbors (less than 4) are cyan. How might you expect the atoms to rearrange themselves to lessen the discrepancy?

Below to the left find a comparison between an experimental high-res electron microscope image (top: green) of a "nanotwin end" in germanium, and a simulated image (bottom: grey) of the jmol model above. Any ideas how to explain the difference?

Here is a darkfield image of a pair of <111> nanotwins found in gigascale integrated circuit silicon as manufacturers were working to scale up to the routine production of 12 inch diameter wafers.

Below find comparison between that experimental Ge image and a physical model put together by Danielle K for a Science Fair project.