Forty Years Study of Fivefold Twinned Structures in Small Particles and Thin Films

Multiple twinning in crystalline solids forming quintuples of twins is known since 1957 (Segall). It ever has attracted the attention not only of crystal growth and crystallography research, but also of cluster physics, physical chemistry, surface science, thin films and materials research. This review gives a comprehensive record of four decades work on fivefold twinned structures (frequently named `multiply twinned structures') in small particles and thin films. After introducing crystallographic aspects of fivefold twinning, an historical review reports on beginning and spread out of the exploration as well as its broad extension to various fields, techniques and materials. The main issues of fivefold twinned structures, i.e. materials and processes involved, formation mechanisms, and stability and lattice defects, respectively, are treated in detail and illustrated by various examples. Accompanied by an almost complete list of references this review may not only make available results and experience of previous work in a greater context, but also stimulate future studies on this phenomenon.