Topology of vibrational modes predict plastic events in glasses

TL;DR

This study links the topological features of vibrational modes in glasses to their plastic deformation behavior, showing that negative topological defects predict where plastic events occur under shear.

Contribution

It introduces a novel approach connecting vibrational mode topology with plastic events in glasses, providing insights into their microscopic deformation mechanisms.

Findings

Negative topological defects correlate with plastic event locations.

Vibrational mode topology predicts deformation sites.

Structural defects in glasses influence plasticity.

Abstract

The plastic deformation of crystalline materials can be understood by considering their structural defects such as disclinations and dislocations. Although glasses are also 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 with 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.