# The Glassy Solid as a Statistical Ensemble of Crystalline Microstates

## TL;DR

This paper models glassy solids as statistical ensembles of crystalline microstates, demonstrating that their structural properties can be predicted from first principles without experimental data.

## Contribution

It introduces a novel ensemble-based approach to describe glasses, linking their structure to crystalline local minima and enabling fully predictive modeling.

## Key findings

- Accurately reproduces RDF and XRD for amorphous silicon
- Replicates key structural features of glassy silica
- Supports the ensemble nature of glassy solids

## Abstract

Motivated by the concept of partial ergodicity, we present an alternative description of covalent and ionic glassy solids as statistical ensembles of crystalline local minima on the potential energy surface. We show analytically that the radial distribution function (RDF) and powder X-ray diffraction (XRD) intensity of ergodic systems can be rigorously formulated as statistical ensemble averages, which we evaluate for amorphous silicon and glassy silica through the first-principles random structure sampling. We show that using structures with unit cells as small as 24 atoms, we are able to accurately replicate the experimental RDF and XRD pattern for amorphous silicon as well as the key structural features for glassy silica, thus supporting the ensemble nature of the glasses and opening the door to fully predictive description without the need for experimental inputs.