Icosahedral Ordering in the Lennard-Jones Liquid and Glass

Abstract

We have simulated the cooling of Lennard-Jones fluids from liquid temperatures to below the glass transition by using molecular-dynamics calculations and periodic boundary conditions. At higher temperatures the "inherent" structure is independent of temperature, but slightly above the glass transition temperature $T_g$ the structure changes and local fivefold symmetry becomes more prominent. At $T_g$ this process is slow and a hysteresis is observed on heating. The low-temperature two-component glass has a cluster of interpenetrating and face-sharing icosahedra percolating throughout the sample.