Generating ultrastable glasses by homogenizing the local virial stress

TL;DR

This paper introduces a new protocol for creating ultrastable glasses by iteratively reducing local virial stress fluctuations, resulting in glasses with enhanced stability and structural order compared to thermally annealed states.

Contribution

The study presents a novel algorithm that homogenizes local virial stress to produce ultrastable glasses with improved stability and structural features.

Findings

Virial homogenized glasses show increased kinetic stability.

VHG have more locally favored structures like icosahedra.

Melting occurs via localized events during heating.

Abstract

In recent years, the possibility of algorithmically preparing ultra-stable glasses (UG), i.e., states that lie very deep in the potential energy landscape, has considerably expanded our understanding of the glassy state. In this work, we report on a new protocol for ultrastable glass preparation that iteratively modifies the particle diameters to reduce local virial stress fluctuations. We apply the algorithm to an additive Lennard-Jones mixture and show that, compared to the states obtained via thermal annealing, virial homogenized glasses (VHG) are characterized by a considerable increase in both kinetic stability and the number of locally favored structures (icosahedra). We also consider the melting dynamics during heating ramps and show that it occurs via an accumulation of localized events. Our results highlight the connection between the thermodynamic and mechanical stability of ultra-stable glassy states.