Many-body correlations are non-negligible in both fragile and strong glassformers

TL;DR

This paper extends mode-coupling theory to include higher-order correlations, revealing their significant role in the glass transition for both fragile and strong glassformers, and showing they influence the predicted dynamics.

Contribution

It introduces a systematic extension of mode-coupling theory incorporating static triplet and dynamic correlations, improving understanding of glass transition mechanisms.

Findings

Static triplet correlations qualitatively alter the glass-transition diagram.

A competition exists between static and dynamic correlations affecting glass stability.

Higher-order correlations are non-negligible in both fragile and strong glassformers.

Abstract

It is widely believed that the emergence of slow glassy dynamics is encoded in a material's microstructure. First-principles theory [mode-coupling theory (MCT)] is able to predict the dramatic slowdown of the dynamics from only static two-point correlations as input, yet it cannot capture all of the observed dynamical behavior. Here we go beyond two-point spatial correlation functions by extending MCT systematically to include higher-order static and dynamic correlations. We demonstrate that only adding the static triplet direct correlations already qualitatively changes the predicted glass-transition diagram of binary hard spheres and silica. Moreover, we find a non-trivial competition between static triplet correlations that work to stabilize the glass state, and dynamic higher-order correlations which destabilize it for both materials. We conclude that the conventionally neglected static triplet direct correlations as well as higher-order dynamic correlations are in fact non-negligible in both fragile and strong glassformers.