Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 46: Nanostructures and Clusters
O 46.1: Talk
Wednesday, March 13, 2013, 10:30–10:45, H45
MSinHn aggregates: from simple building blocks to highly magnetic functionalized materials — •Dennis Palagin and Karsten Reuter — TU München
The use of multi-doped endohedral Si clusters as building blocks for assembly at the nanometer scale has attracted much attention due to promising cage-like geometries and easy-to-tune electronic properties [1]. For instance, in these structures the high magnetic moments of transition metal dopants can be preserved through minimizing the cage-dopant interaction by hydrogen termination [2]. A variable amount of hydrogen atoms may be used to control the number of bonding sites of the cluster, to which another cage can be attached. With a tool box of monomers with differing numbers of "docking sites", it seems possible to build network architectures of any morphology. Here we scrutinize this proposition through density-functional theory based global geometry optimization. Our results show that, unlike in case of typical clathrate structures, MSi20H20 clusters tend to aggregate through the formation of double Si-Si "bridges" between the monomers. Intriguingly, such aggregates possess very high magnetic moments due to their virtually isolated dopants. We screen a larger range of possible oligomers and critically discuss the resulting geometrical and electronic structures.
[1] T. Iwasa and A. Nakajima, J. Phys. Chem. C 116, 14071 (2012).
[2] D. Palagin and K. Reuter, Phys. Rev. B 86, 045416 (2012).