Résumé
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.