The Origin of the Fragile-to-Strong Crossover in Liquid Silica as Expressed by its Potential Energy Landscape

TL;DR

This paper investigates the fragile-to-strong transition in liquid silica by analyzing its potential energy landscape, revealing a low-energy cutoff that influences structural properties and explains the crossover and avoidance of the Kauzmann paradox.

Contribution

It demonstrates that a low-energy cutoff in the potential energy landscape underpins the fragile-to-strong crossover in liquid silica, linking structural defects to this phenomenon.

Findings

Low-energy cutoff in the PEL of silica.

Vanishing defects near the cutoff.

Explains the fragile-to-strong crossover and Kauzmann paradox avoidance.

Abstract

The origin of the fragile-to-strong crossover in liquid silica is characterized in terms of properties of the potential energy landscape (PEL). Using the standard BKS model of silica we observe a low-energy cutoff of the PEL. It is shown that this feature of the PEL is responsible for the occurrence of the fragile-to-strong crossover and may also explain the avoidance of the Kauzmann paradox. The number of defects, i.e. deviations from the ideal tetrahedral structure, vanishes for configurations with energies close to this cutoff. This suggests a structural reason for this cutoff.