Fig. 1.

Discrepancy between MD rates and TST predictions. (A) Simulation cell ($20[1\overline{1}0]\times 20[111]\times 10[\overline{1}\overline{1}2]$) with a screw dislocation along the $x$-direction, visualized by OVITO (26). Atoms are colored according to their centrosymmetric parameter (CSP), given an fcc crystal structure (12 neighbors). The atoms with $\text{CSP}>1$ are extracted to visualize the dislocation core structure. The screw dislocation changes the slip plane from $(111)$ to $(11\overline{1})$ following the Freidel–Escaig mechanism (27). The three Escaig–Schmid stresses components ${\mathit{\tau }}_{\text{app}}=({\sigma }_{\mathrm{e}}^{\mathrm{g}},{\sigma }_{\mathrm{s}}^{\mathrm{c}},{\sigma }_{\mathrm{e}}^{\mathrm{c}})$ controlling the cross-slip process are applied on the two slip planes. The cross-slipped dislocation moves along the cross-slip plane (blue arrow) if ${\sigma }_{\mathrm{s}}^{\mathrm{c}}$ is applied and finally annihilates at the free surface. (B) Converged minimum-energy paths of cross-slip, calculated at zero stress ${\mathit{\tau }}_{\text{app}}=0$ and fixed applied stress ${\mathit{\tau }}_{\text{app}}=(-0.6,-0.8,0.8)\text{GPa}$. The positive directions of the shear stresses are marked as arrows in A. (C) Cross-slip rates at different temperatures obtained by MD simulations (solid line) and predicted by TST Eq. 1 (dashed line) under fixed applied stress ${\mathit{\tau }}_{\text{app}}$.