Topological Features of Structural Relaxations in a Two-Dimensional Model Atomic Glass II

The topological features of atom motions in a high-temperature melt, a sub-cooled melt above T_g, and a glass below T_g, were analysed in detail by means of a two-dimensional molecular dynamics simulation. A striking analogy was observed between the structure and properties of the liquid-like material separating quasi-ordered domains of atom clusters, and high-angle grain boundaries. The main feature of the structural relaxation below the melting point, both above and below T_g was the gradual dissolution and disappearance of the liquid-like material, permitting increasing order in the previously quasi-ordered domains and a growth in their sizes. In these processes, many sequences reminiscent of cancellation of dislocation pairs, or mutual reactions to give more stable sets, were observed.