Are clusters physical entities?

Abstract

Complex metallic alloys frequently exhibit atomic clusters as structural units. In quasicrystals, they are densely arranged retaining an overall long-range quasi- periodic translational order. Thus, clusters are geometrical entities. The often posed question is, whether these are also responsible for physical properties. Fracture experiments and simulations strongly point towards a positive answer. However, a recent analysis of experimental fracture surfaces questions a signature of the clusters. From the self-affine behavior of a model system it is shown that the findings cannot vitiate the role of the clusters in the fracture process. © by Oldenbourg Wissenschaftsverlag.