On the protocol dependence of plasticity in ultra-stable amorphous solids

TL;DR

This paper investigates how the initial preparation protocol affects the scaling of plasticity in ultra-stable amorphous solids, concluding that apparent protocol dependence is a pre-asymptotic effect rather than a fundamental property.

Contribution

The study demonstrates that the observed protocol dependence in the scaling of plasticity is a transient effect, and provides a simple model explaining the data without assuming protocol dependence.

Findings

Scaling relation is pre-asymptotic, not fundamental.

Protocol dependence is an apparent effect in initial data.

A simple model explains the observed behavior without protocol dependence.

Abstract

While perfect crystals may exhibit a purely elastic response to shear all the way to yielding, the response of amorphous solids is punctuated by plastic events. The prevalence of this plasticity depends on the number of particles $N$ of the system, with the average strain interval before the first plastic event, $\overline{\Delta\gamma}$, scaling like $N^\alpha$ with $\alpha$ negative: larger samples are more susceptible to plasticity due to more numerous disorder-induced soft spots. In this paper we examine this scaling relation in ultra-stable glasses prepared with the Swap Monte Carlo algorithm, with regard to the possibility of protocol-dependent scaling exponent, which would also imply a protocol dependence in the distribution of local yield stresses in the glass. We show that, while a superficial analysis seems to corroborate this hypothesis, this is only a pre-asymptotic effect and in fact our data can be well explained by a simple model wherein such protocol dependence is absent.