MSi20H20 Aggregates: From Simple Building Blocks to Highly Magnetic Functionalized Materials

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• 作者：Dennis Palagin ; Karsten Reuter
• 刊名：ACS Nano
• 出版年：2013
• 出版时间：February 26, 2013
• 年：2013
• 卷：7
• 期：2
• 页码：1763-1768
• 全文大小：366K
• 年卷期：v.7,no.2(February 26, 2013)
• ISSN：1936-086X

文摘

Density-functional theory based global geometry optimization is used to scrutinize the possibility of using endohedrally doped hydrogenated Si clusters as building blocks for constructing highly magnetic materials. In contrast to the known clathrate-type facet-sharing, the clusters exhibit a predisposition to aggregation through double Si鈥揝i bridge bonds. For the prototypical CrSi₂₀H₂₀ cluster we show that reducing the degree of hydrogenation may be used to control the number of reactive sites to which other cages can be attached, while still preserving the structural integrity of the building block itself. This leads to a toolbox of CrSi₂₀H_20鈥?n monomers with different number of double 鈥渄ocking sites鈥? that allows building network architectures of any morphology. For (CrSi₂₀H₁₈)₂ dimer and [CrSi₂₀H₁₆](CrSi₂₀H₁₈)₂ trimer structures we illustrate that such aggregates conserve the high spin moments of the dopant atoms and are therefore most attractive candidates for cluster-assembled materials with unique magnetic properties. The study suggests that the structural completion of the individual endohedral cages within the doubly bridge bonded structures and the high thermodynamic stability of the obtained aggregates are crucial for potential synthetic polimerization routes via controlled dehydrogenation.

Keywords:

doped silicon clusters; magnetic building blocks; cluster compounds; material assembly