Simulation studies were made of a morphological instability arising in dislocation dynamics. When an initially straight dislocation line was driven by a stress whose magnitude grows along the direction of dislocation motion, vibrational modes of the dislocation line with wavelength above a threshold value become linearly unstable. Molecular dynamics simulation studies of screw dislocations in Al demonstrate the onset of the instability during dislocation pair annihilation and annihilation at a crack tip. The wavelength of the unstable vibrational mode observed in each case agreed with the predictions of theoretical analysis. The role of temperature in nucleating the instability

was considered, and it was speculated how instabilities in dislocation motion could affect the density of threading dislocations during the growth of hetero-epitaxial thin films.

Molecular Dynamics Simulations of Dislocation Instability in a Stress Gradient. M.Li, R.L.B.Selinger: Physical Review B, 2003, 67[13], 134108 (6pp)