Dynamic properties of screw dislocations in Cu: A molecular dynamics study

The dynamic properties of a single dislocation in Cu under an applied stress are studied using constant stress and temperature molecular dynamics. The dislocation is found to accelerate to a terminal velocity. The terminal velocity initially increases linearly with stress and finally approaches the shear wave velocity asymptotically. In the linear regime the drag coefficient is determined. The results are comparable with the experimental data at high temperatures and an order of magnitude higher at low temperatures. The dislocation width is found to oscillate periodically, with a period determined by the stacking fault energy and the elastic coefficients.