Dynamical Correlations near Dislocation Jamming

作者：Laurson Lasse^*; Miguel M Carmen; Alava Mikko J

来源：Physical Review Letters, 2010, 105(1): 015501.

DOI：10.1103/PhysRevLett.105.015501

Dislocation assemblies exhibit a jamming or yielding transition at a critical external shear stress value sigma = sigma(c). Here we study the heterogeneous and collective nature of dislocation dynamics within a crystal plasticity model close to sigma(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 chi(*)(4) diverges as chi(*)(4) similar to (sigma - sigma(c))(-alpha), with alpha approximate to 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 xi(y) in the direction perpendicular to the dislocation glide motion.

• 出版日期2010-6-28