| A new mechanism of misfit dislocation nucleation in surface nanowires and nanoislands (quantum dots) growing on substrates is suggested and theoretically described. The mechanism represents the nucleation of a non-crystallographic partial dislocation whose Burgers vector magnitude continuously grows during the nucleation process. The nucleation occurs by a nanoscale ideal shear that involves collective displacements of atoms of a surface nanowire/ nanoisland. It is shown that the new mechanism of dislocation formation in surface nanowires/ nanoislands effectively competes with the standard nucleation of a perfect dislocation at a free surface and its further glide towards the nanowire/nanoisland base center. |
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