Generating Ultrastable Glasses by Homogenizing the Local Virial Stress

The algorithmic preparation of ultrastable glasses (UG) has considerably expanded our understanding of the glassy state. In this work, we report on a new protocol for UG preparation in a model colloidal glass that iteratively modifies particle diameters to reduce local virial stress fluctuations, effectively homogenizing the local mechanical environment of individual particles. We apply the algorithm to an additive Lennard-Jones mixture and show that, compared to the states obtained via thermal annealing, virial homogenized glasses are characterized by a considerable increase in both kinetic stability and the number of locally favored structures, and melt during heating ramps via an accumulation of localized events. Our results show that microscopic mechanical homogeneity, a widely applicable concept, can give rise to ultrastability.