# Yielding of a Model Glassformer: an Interpretation with an Effective System of Icosahedra

## TL;DR

This study investigates how shear rates influence shear localization in a model glassformer, linking local structural icosahedra formation to effective temperature changes during deformation.

## Contribution

It introduces an interpretation of glassy yielding using an effective system of icosahedra, connecting local structure to shear response and localization behavior.

## Key findings

- Shear localization depends on temperature and shear rate.
- Higher effective temperatures correlate with shear localization regions.
- Shear induces significant local temperature increases before steady state.

## Abstract

We consider the yielding under simple shear of a binary Lennard-Jones glassformer whose super-Arrhenius dynamics are correlated with the formation of icosahedral structures. We recast this glassformer as an effective system of icosahedra [Pinney et al. J. Chem. Phys. 143 244507 (2015)]. Looking at the small-strain region of sheared simulations, we observe that shear rates affect the shear localisation behavior particularly at temperatures below the glass transition as defined with a fit to the Vogel-Fulcher-Tamman equation. At higher temperature, shear localisation starts immediately upon shearing for all shear rates. At lower temperatures, faster shear rates can result in a delayed start in shear localisation; which begins close to the yield stress. Building from a previous work which considered steady-state shear [Pinney et al. J. Chem. Phys. 143 244507 (2016)], we interpret the response to shear and the shear localisation in terms of a \emph{local} effective temperature with our system of icosahedra. We find that the effective temperatures of the regions undergoing shear localisation increase significantly with increasing strain (before reaching a steady state plateau).