The Peierls stress of the a/2 screw dislocation belonging to the shuffle set was calculated for Si using density functional theory. The effect of boundary conditions was checked by using 2 models: the super-cell method where a periodic array of dislocations was considered, and the cluster method where a single dislocation was embedded in a small cluster. The Peierls stress was under-estimated with the super-cell and over-estimated with the cluster. These contributions were calculated and the Peierls stress was determined in the range between 2.4 x 10-2 and 2.8 x 10-2eV/Å3 . When moving, the dislocation follows the {111} plane going through a low energy metastable configuration and never follows the 100 plane, which includes a higher energy metastable core configuration.

First Principles Determination of the Peierls Stress of the Shuffle Screw Dislocation in Silicon. L.Pizzagalli, P.Beauchamp: Philosophical Magazine Letters, 2004, 84[11], 729-36