Correlated Atomic Dynamics in Metallic Glass Forming Systems - Messages from Computer Simulations

Due to their amorphous structure, finite temperature glass-forming melts and glasses show a competition between an immense number of atomic arrangements, a feature not found in a similar pronounced way in crystalline samples. Changes between the arrangements lead to sluggish, non-exponential decay of configurations, typical for this class of materials and leading to glass formation. For metallic glasses and their melts, we consider findings from actual computer simulations of glass dynamics, which allow relating the time-decay characteristics of configurations with structural changes on the microscopic, atomistic level. Thereby we bridge more than eight orders in time, from atomic vibrations on the sub-pico second range to meso-scale micro second evolutions. In the presentation, key topics are shortand medium-range order of the amorphous structure, basic vibration induced excitations, the accumulation principle, and structure conserving correlations between excitations.