The mechanical behavior of GaAs was investigated by using nano-indentation, and a molecular dynamics analysis based upon the Tersoff potential. Particular attention was paid to the evolutionary aspects of the dislocation activity during deformation. The transition from elastic-to-plastic deformation behavior was clearly observed as a sudden displacement excursion which occurred in the load–displacement curves at higher loads (single pop-in), or for faster impact velocity and higher temperature (multiple pop-ins). Even for an ultra-small penetration depth (<3nm), the molecular dynamics simulation showed that GaAs deformed plastically, and a good description of the results was given. The plastic deformation occurred due to the anticipated change in twinning and/or dislocation motion. Dislocation nucleation occurred within the material, near to the top of the surface and generated loops in the {111} slip planes. The molecular dynamics analysis of the deformation behavior showed an agreement with that of previous atomic force microscopy and transmission electron microscopy experiments.

Atomistic Modeling of Dislocation Activity in Nanoindented GaAs. S.R.Jian, T.H.Fang, D.S.Chuu, L.W.Ji: Applied Surface Science, 2006, 253[2], 833-40