Perfect and partial Frank-Read sources in silicon: A simulation

Abstract

The first step of the Pirouz model for mechanical twinning, which involves the emission of a partial dislocation by a dislocation source, has been investigated in the case of silicon with the help of a dynamical mesoscopic simulation. The emission of partial dislocations is found to occur in a domain of high stresses and low temperatures, the latter being close to the brittle-ductile transition temperature. The transition between perfect and partial emission is shown to be related to the transition between the length-independent and the length-dependent regimes of the stress against velocity law for dislocation motion over the Peierls barriers. The influences of the anisotropy of partial dislocation mobilities, the applied stress and the temperature on the dynamic behaviour of the dislocation sources are discussed.