Role of distant vortex–antivortex dipoles in triggering shear-band flow

Ascertain the physical role and mechanism by which isolated, large vortex–antivortex defect dipoles located far from the aligned chain of topological defects influence or trigger shear-band formation in two-dimensional ultrastable glasses under athermal quasistatic shear, including whether they redistribute stress and transmit nonlinear energy to the band.

Background

In the simulations, the authors repeatedly observe an isolated vortex–antivortex dipole far from the shear band during each plastic stress drop. This dipole is not observed without a concomitant shear band and consistently disappears as the band begins to flow, suggesting a potential causal linkage.

The authors explicitly state that the role of these distant dipoles remains unclear, though they appear connected to stress redistribution and nonlinear energy transmission that could initiate or sustain the flow along the pre-existing chain of topological defects. Clarifying this mechanism would help bridge microscopic defect dynamics and macroscopic shear-band behavior.