Fluctuation - induced nucleation and dynamics of the kinks on dislocation. Soliton and oscillation regimes in 2D Frenkel-Kontorova model

Abstract

Numerical simulation of the dislocation motion in 2D Frenkel - Kontorova (FK) model in the thermostat shows an unusual dynamical behavior. It appears that ''kink'' regime of dislocation gliding takes place in a certain region of parameters of the model but, in disagreement with the common views about the dislocation motion under plastic deformation condition, the kinks appear to be similar to sine-Gordon solitons despite the discreteness of the lattice, damping and thermal fluctuations. At high enough stresses and temperatures the motion of the dislocation is accompanied by its oscillations rather than kink nucleation.Comment: 5 pages, RevTeX, 5 PostScript figures, rewritten and extended version, accepted for publication in Phys. Rev.