Dynamic arrest and glass formation induced by self-aggregation of icosahedral clusters in Zr1-xCux alloys

Using ab initio molecular dynamics simulations, we find direct evidence that icosahedral clusters have a strong tendency to aggregate in Zr1-xCux liquids. Remarkably, the dynamic arrest effect is much more significant in aggregated icosahedral clusters than in nonaggregated ones by a factor of 2 or more. Simulations using a lattice model demonstrate that the dynamic arrest effect resulting from the aggregation of icosahedral clusters may be a fundamental characteristic of the glass transition. Our studies provide an atomistic structural mechanism for dynamic arrest and glass formation.