ISI Foundation, Viale S. Severo 65, 10133 Torino, Italy.
Phys Rev Lett. 2010 Jul 2;105(1):015501. doi: 10.1103/PhysRevLett.105.015501. Epub 2010 Jun 28.
Dislocation assemblies exhibit a jamming or yielding transition at a critical external shear stress value σ=σ{c}. Here we study the heterogeneous and collective nature of dislocation dynamics within a crystal plasticity model close to σ{c}, by considering the first-passage properties of the dislocation dynamics. As the transition is approached in the moving phase, the first-passage time distribution exhibits scaling, and a related peak dynamical susceptibility χ{4}{} diverges as χ{4}{}∼(σ-σ{c}){-α}, with α≈1.1. We relate this scaling to an avalanche description of the dynamics. While the static structural correlations are found to be independent of the external stress, we identify a diverging dynamical correlation length ξ{y} in the direction perpendicular to the dislocation glide motion.
位错组装体在外剪切应力值σ=σ{c}下表现出阻塞或屈服转变。在这里，我们通过考虑位错动力学的首次通过特性，研究了接近σ{c}的晶体塑性模型中位错动力学的不均匀和集体性质。在移动相中接近转变时，首次通过时间分布表现出标度，相关的动态磁化率 χ{4}{}发散，χ{4}{}∼(σ-σ{c}){-α}，其中 α≈1.1。我们将这种标度与动力学的雪崩描述联系起来。虽然静态结构相关性与外部应力无关，但我们发现垂直于位错滑移运动方向的动态相关长度 ξ{y}会发散。
