Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 75: Particles and clusters
O 75.2: Vortrag
Donnerstag, 29. März 2012, 16:15–16:30, MA 041
Endohedral doping of hydrogenated Si fullerenes: A route to magnetic Si building blocks? — •Dennis Palagin and Karsten Reuter — TU München
Metal encapsulation was found to produce fullerene and other polyhedral cage structures of silicon and therewith provides an intriguing novel nanoform of Si for device applications. In these structures the cage geometry is stabilized through a strong interaction with the endohedral dopant atom. The recent suggestion that also hydrogen termination of Si16 could yield an empty fullerene configuration has raised hopes that metal-doping corresponding Si16H16 fullerenes would yield cage structures with minimized M-Si interaction [1]. With the atomic character of e.g. magnetic dopants then likely conserved, this would offer a route to develop Si fullerene species with large magnetic moments. We scrutinize this proposition through density-functional theory based global geometry optimization. While we can confirm that the fullerene is indeed the ground-state structure of Si16H16, this is unfortunately not the case for Ti or Cr dopant atoms. Strongly distorted or even broken cages are instead significantly more stable. We therefore screen a larger range of dopant atoms and critically discuss the resulting M-Si interaction in all of these cases.
[1] V. Kumar and Y. Kawazoe, Phys. Rev. Lett. 90, 055502 (2003).