Screw dislocation dynamics in confinement-induced layering of Yukawa liquids after quenching

Abstract

Screw dislocation filaments (SDFs) with undefined phases and winded around by helical isophase fronts are fundamental topological defects, which can be used for characterizing the disorder of layered solids and unstable traveling waves. Here, we numerically demonstrate the observation of fluctuating SDFs in the transient relaxation of confinement-induced layering of Yukawa liquids after quenching. We classify the generic dynamical behaviors of screw dislocations (SDs) and unravel their topological origins, which are elusive fundamental issues for general layered systems. It is found that the spatiotemporal growth and decay of layer undulation instability causing sequential rupture and reconnection of a stack of layers are the keys for the formation of SD loops or strings of connected SDFs with alternating helicities, and their spatiotemporal fluctuations. The breaking and reconnection of two approaching SDFs with opposite or the same helicities can form two new separated SDFs. This causes an SD loop to be shed from or merged with another SD loop. The total number of SDs decreases and levels off with increasing time from quenching.