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

[摘要] 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 Frankâ€�?�Kasper polyhedron has been obtained for M@X₁₆, X = Si and Ge. These clusters show high stability and large highest occupiedâ€�?�lowest unoccupied molecular orbital (HOMOâ€�?�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.

[学科分类] 材料工程

[关键词] Silicon;fullerenes;Frankâ€�?�Kasper polyhedron;cubic.