Comparison of computational methods for predicting plastic activity in amorphous materials

Imposing an external driving, amorphous solids can flow via a succession of plastic rearrangement of localized particles. Numerous numerical and experimental studies have shown that loci of plastic instability in glasses are triggered by spatially localized soft spots in direct analogy with dislocations present in crystalline solids, although the population and microscopic structure of the former being significantly different from the latter. The detection and nature of such “amorphous defects” have received a lot of attention, one of the goals being to predict from the microscopic structure itself which regions are likely to undergo a rearrange upon deformation. In this study, we investigate plasticity in a model glass former driven via Athermal Quasistatic Shear. Using SWAP Monte Carlo, we are able to prepare equilibrium amorphous configurations from high to very low temperatures, which translates in controlling the crossover behavior from ductile to brittle glasses. We compute various structural indicators ranging from purely structural to highly non-linear methods that require the knowledge of the interactions between constituents. We fully quantify how well these metrics compete with each other for various glass stabilities and how far in the deformation (here the strain) do they perform in predicting plastic events. Moreover, we are capable of extracting estimates for the full spatial distribution of plastic defects both in quiescent glasses and across the yielding transition, allowing to microscopically characterize and draw a line between ductile and brittle materials.