The Peierls stress of a straight screw dislocation was studied by using an ab initio molecular dynamics simulation. The generalized stacking fault energy was no longer a continuous function of the displacement of the slip plane as a function of structural relaxation. The Peierls-Nabarro theory then failed to describe properties of the dislocation core, such as the Peierls stress. Direct simulations of dislocation slip dynamics were also performed, and the Peierls stress was derived without requiring any artificial modelling of the dislocation core. Following structural relaxation, sudden bond switching near to the dislocation core occurred. This implied the existence of a narrow dislocation core. Crystal deformation in the [¯110] direction, parallel to the Burgers vector, caused dislocation dipoles to slip on a (111) plane towards [¯1¯12]. Slip motion ceased following movement through 1 translational period of the lattice. This was due to elastic interaction between dislocations. The bonds around the core structure were weakened just after slip. Excellent agreement with experimental results was obtained.

Ab initio Calculation of Peierls Stress in Silicon. M.Miyata, T.Fujiwara: Physical Review B, 2001, 63[4], 045206 (9pp)