Evolution of covalent networks under cooling: contrasting the rigidity window and jamming scenarios

TL;DR

This paper investigates how covalent network structures evolve during cooling, revealing that weak interactions influence the rigidity transition, aligning it more with mean-field behavior and challenging previous critical point theories.

Contribution

It introduces a model incorporating weak non-covalent interactions, demonstrating their impact on the rigidity transition in covalent networks and providing an alternative view on the intermediate phase.

Findings

Weak interactions alter the rigidity transition at low temperatures.

The transition becomes mean-field, losing critical point characteristics.

Vibrational modes resemble those near jamming, not fractons.

Abstract

We study the evolution of structural disorder under cooling in supercooled liquids, focusing on covalent networks. We introduce a model for the energy of networks that incorporates weak non-covalent interactions. We show that at low-temperature, these interactions considerably affect the network topology near the rigidity transition that occurs as the coordination increases. As a result, this transition becomes mean-field and does not present a line of critical points previously argued for, the "rigidity window". Vibrational modes are then not fractons, but instead are similar to the anomalous modes observed in packings of particles near jamming. These results suggest an alternative interpretation for the intermediate phase observed in chalcogenides.