Nanoclusters and interfaces under ion irradiation: Inverse Ostwald ripening and pattern formation

Ion irradiation of solids can change well-known processes of structure evolution dramatically. For instance, the thermally activated corsening of nanocluster ensembles embedded in a matrix (i.e. Ostwald ripening) can change to inverse Ostwald ripening under ion irradiation if ion-beam-induced atomic displacements dominate the kinetics. Inverse ripening means that the nanocluster sizes no longer coarsens with time, but all nanocluster reach asymtodically the same size. On the other hand, intense ion-beam-induced displacements can result in self-organization of ordered surface pattern. Here, the competion between thermally activated smoothening and the ion-beam-induced roughening are the driving forces for surface patterning.