Effects of topological order on vibrational dynamics in simple close-packed glasses

Abstract The effect of topological local order on vibrational dynamics in simple one-component glasses is analyzed numerically. The vibrational density of states of a glass with icosahedral local order is found to be similar to that of the σ-phase, a Frank–Kasper crystal, which represents a counterpart periodic phase for this glass. Optic-like longitudinal vibrational modes and two incommensurate length scales having analogues in the σ-phase are observed in this glass. This pattern of vibrational dynamics is in contrast with that generally ascribed to simple one-component glasses: e.g. a Lennard–Jones (LJ) glass is characterized by a single length scale and supports only modes with acoustic behavior.