Solitonlike Motion of a Dislocation in a Lattice

It is shown that an almost loss-free mode of motion for a straight screw dislocation exists in a three-dimensional lattice. Thus dislocations can move at velocities of the order of half the speed of sound at stress levels corresponding to a strain $s<\mathrm{}{10}^{-3\mathrm{}}$, even in the presence of a much higher static Peierls stress. A strain of this magnitude can be provided by lattice vibrations, so that the dislocation-phonon complex moves in a solitonlike mode, requiring no external stress.