Fig. 3: Kink nucleation mechanism and the observation of cross-slip locking.

a Snapshots of atomic configurations along the screw dislocation, illustrating kink nucleation during glide. (i) The initially straight screw dislocation line. (ii) A kink pair nucleates (indicated by the black arrows) and migrates along the dislocation line (dashed arrow). (iii) Kink-pair migration leads to the net motion of the screw dislocation line. (iv) Another kink pair nucleates (indicated by the red arrows) and migrates. Only the dislocation core atoms are shown and the atoms are colored by coordinates in the glide direction \([1\bar{1}2]\). b Simulation velocity vs. stress results for the screw dislocation at 1200 K; the circles show anomalous points yielding a significantly lower average velocity, associated with the formation of cross-slip locking. Details of the dislocation configurations are shown in (c, d). c Displacement vs. time curve of a screw dislocation under a shear stress of 1.4 GPa at 1200 K in the random sample. The inset shows the formation of cross-slip locking during screw dislocation glide. d Corresponding displacement vs. time curve of a screw dislocation under a shear stress of 2.0 GPa at 1200 K in the SRO sample. The inset figure shows the formation and unlocking of cross-slip locking during screw dislocation glide. e Perspective view of the dislocation line with cross-slip locking. The blue region and red region are on slip planes with different z coordinates. f Dislocation line with cross-slip locking viewed from the y direction. The red segment of the dislocation line in on plane 1 and the blue segment is on plane 2; the two segments are connected by two jogs with a height of 2d₁₁₀. g Dislocation line with cross-slip locking viewed from the z direction. In e–g, only the atoms around the screw dislocation line are shown and are colored by the coordinates in the z direction. The green line represents the <111> screw dislocation line.