Novel caged clusters of silicon: Fullerenes, Frank-Kasper polyhedron and cubic

TLDR: A review of metal encapsulated caged clusters of Si and Ge obtained from computer experiments based on an ab initio pseudopotential method can be found in this article, where it is shown that one M atom changes drastically the properties of Si/Ge clusters and that depending upon the size of the M atom, cages of 14, 15, and 16 Si as well as Ge atoms are formed.

Abstract: We review recent findings of metal (M) encapsulated caged clusters of Si and Ge obtained from computer experiments based on an ab initio pseudopotential method. It is shown that one M atom changes drastically the properties of Si and Ge clusters and that depending upon the size of the M atom, cages of 14, 15, and 16 Si as well as Ge atoms are formed. In particular M@Si16 silicon fullerene has been obtained for M= Zr and Hf, while a Frank-Kasper polyhedron has been obtained for M@X16, X = Si and Ge. These clusters show high stability and large highest occupied-lowest unoccupied molecular orbital (HOMO-LUMO) gaps which are likely to make these species strongly abundant. A regular icosahedral M@X12 cluster has also been obtained for X = Ge and Sn by doping a divalent M atom. Interactions between clusters are rather weak. This is attractive for developing self-assembled cluster materials.