Clustering of negative topological charge precedes plastic failure in 3D glasses

Abstract

The deformation mechanism in amorphous solids subjected to external shear remains poorly understood because of the absence of well-defined topological defects mediating the plastic deformation. The notion of soft spots has emerged as a useful tool to characterize the onset of irreversible rearrangements and plastic flow, but these entities are not clearly defined in terms of geometry and topology. In this study, we unveil the phenomenology of recently discovered, precisely defined topological defects governing the microscopic mechanical and yielding behavior of a model 3D glass under shear deformation. We identify the existence of vortex-like and anti-vortex-like topological defects within the 3D non-affine displacement field. The number density of these defects exhibits a significant anti-correlation with the plastic events, with defect proliferation-annihilation cycles matching the alternation of elastic-like segments and catastrophic plastic drops, respectively. Furthermore, we observe collective annihilation of these point-like defects via plastic events, with large local topological charge fluctuations in the vicinity of regions that feature strong non-affine displacements. We reveal that plastic yielding is driven by several large sized clusters of net negative topological charge, the massive annihilation of which triggers the onset of plastic flow. These findings suggest a geometric and topological characterization of soft spots and pave the way for the mechanistic understanding of topological defects as mediators of plastic deformation in glassy materials.

Accepted for publication in PNAS Nexus

References in corpus (10)

• Disclinations, dislocations and continuous defects: a reappraisal
• Topology of vibrational modes predict plastic events in glasses
• Anomalous Elasticity and Screening in Amorphous Solids
• Introduction to topological defects: from liquid crystals to particle physics
• Tensor Electromagnetism and Emergent Elasticity in Jammed Solids
• Topological defects reveal the plasticity of glasses
• Predicting plasticity of amorphous solids from instantaneous normal modes
• Geometric Theory of Mechanical Screening in two-dimensional solids
• Normal modes, and acoustic properties, of an elastic solid with line defects
• Inherent-State Melting and the Onset of Glassy Dynamics in Two-Dimensional Supercooled Liquids

Cited by in corpus (8)

• Experimental identification of topological defects in 2D colloidal glass
• Complete mathematical theory of the jamming transition: A perspective
• The Origin of Sound Damping in Amorphous Solids: Defects and Beyond
• Hedgehog topological defects in 3D amorphous solids
• Topological signatures of collective dynamics and turbulent-like energy cascades in apolar active granular
• Geometric indicators of local plasticity in glasses measured by scanning small-beam diffraction
• On the geometry of topological defects in glasses
• Spotting structural defects in crystals from the topology of vibrational modes