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

TL;DR

This paper investigates the complex dynamics of dislocation motion in a 2D Frenkel-Kontorova model, revealing kink regimes resembling sine-Gordon solitons and oscillatory behaviors under certain conditions, challenging traditional views.

Contribution

It demonstrates that dislocation kinks can behave as sine-Gordon solitons in a discrete lattice, and identifies oscillation regimes at high stress and temperature levels.

Findings

Kink regimes resemble sine-Gordon solitons despite lattice discreteness.

Dislocation motion exhibits oscillations instead of kink nucleation at high stress and temperature.

Unusual dynamical behaviors are observed in the 2D FK model under thermal and stress conditions.

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.