Alladi Ramakrishnan Hall

Topological defects and Plasticity in Amorphous materials

Vinay Vaibhav

University of Milan

Topological defects are ubiquitous in various physical systems, generally appearing in the form of singularities in the order parameter space that are mathematically described by topological invariants and cannot be removed by continuous transformations. Such defects play a crucial role in different fields, ranging from cosmology to solid-state physics and biological matter. Since, these irregularities are defined with respect to an ordered reference configuration, their existence in disordered systems has been debated for a long time. Recent observations of well-defined topological defects in different studies of glassy systems and establishing their close connection with the plasticity of the material have motivated further exploration in this direction. In this talk, I will discuss our recent study where we have observed topological defects in a two-dimensional experimental system composed of colloidal particles interacting via an effective magnetic attraction. Our study confirms the presence of topological defects in the eigenspace of the vibrational frequencies of this experimental 2D amorphous solid. These defects strongly correlate with the vibrational features and spatially correlate with each other and structural “soft spots”, more prone to plastic flow. This sheds light on the complex interplay between topology, disorder, and vibrational behaviour in amorphous systems, paving the way for a deeper understanding of the nuanced relationship between mathematical topology and material behaviour.