Structural changes in the Lennard-Jones supercooled liquid and ideal glass: an improved integral equation for the replica method

TL;DR

This study uses an improved replica integral equation approach to analyze the structural evolution of Lennard-Jones liquids as they approach the glass transition, revealing local fcc-like order in the ideal glass phase.

Contribution

It introduces a refined integral equation method within the replica framework to explore low-temperature structures of supercooled liquids and glasses.

Findings

Identification of a density-dependent temperature where structural changes occur

Development of an additional peak in the radial distribution function

Evidence of local fcc-like short-range order in the ideal glass

Abstract

Framing the glass formation within standard statistical mechanics is an outstanding problem of condensed matter theory. To provide new insight, we investigate the structural properties of the Lennard-Jones fluid in the very-low temperature regime, by using a replicated version of the refined HMSA theory of the liquid state, combined with an appropriate split of the pair potential [Bomont and Bretonnet, J. Chem. Phys. 114, 4141 (2001)]. Our scheme allows one to reach an unprecedented low-temperature domain within both the supercooled liquid and the ideal-glass phase. Therein, a density-dependent temperature is identified, whereupon the radial distribution function experiences clear-cut structural changes, insofar as an additional peak develops in between the main and the second peaks. Such a structural feature points to a local structure of the Lennard-Jones ideal glass with an fcc-like short-range order, in the absence of any long-range order.