Topology of vibrational modes predicts plastic events in glasses

The plastic deformation of crystalline materials can be understood by considering their structural defects such as disclinations and dislocations. Although also glasses are solids, their structure resembles closely the one of a liquid and hence the concept of structural defects becomes ill-defined. As a consequence it is very challenging to rationalize on a microscopic level the mechanical properties of glasses close to the yielding point and to relate plastic events to structural properties. Here we investigate the topological characteristics of the eigenvector field of the vibrational excitations of a two-dimensional glass model, notably the geometric arrangement of the topological defects as a function of vibrational frequency. We find that if the system is subjected to a quasistatic shear, the location of the resulting plastic events correlate strongly with the topological defects that have a negative charge. Our results provide thus a direct link between the structure of glasses prior their deformation and the plastic events during deformation. It remains challenging to understand the relation between mechanical properties of glasses close to the yielding point and plastic behaviors at microscales. Wu et al. examine the plasticity using topological properties of the vibrational modes and identify a correlation between defects and plastic events.

Automated summary

The plastic deformation of crystalline materials can be explained by considering structural defects such as disclinations and dislocations. However, it is challenging to understand the mechanical properties and plastic events of glasses due to their liquid-like structure. In this study, the authors investigate the topological characteristics of a two-dimensional glass model and find that plastic events correlate with topological defects that have a negative charge. This provides a direct link between the structure of glasses and plastic behavior during deformation.