Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 14: Adsorption on semiconductors, oxides and insulators II

O 14.12: Vortrag

Montag, 26. März 2012, 18:45–19:00, MA 041

Adsorption of Au atoms on the h-BN/Rh(111) nanomesh — •Hans Peter Koch, Robert Laskowski, and Peter Blaha — Institute of Material Chemistry, Unversity of Technology, Getreidemarkt 9/165-TC, A-1060 Vienna, Austria

The h-BN/Rh(111) nanomesh [1] consists of a highly corrugated single layer of h-BN on a Rh(111) surface. Due to the lattice mismatch a nanostructure with a periodicity of 3.2 nm is formed. In this nanostructure BN forms ``pores'' of about 2 nm, which are separated by ``wires'', where BN is 0.1 - 0.2 nm further away from the transition metal than in the ``pores''. The ``pores'' of the nanomesh show the extraordinary ability to trap molecules and metallic clusters - forming well-ordered arrays and prohibiting aggregation.

We have theoretically studied the adsorption of Au atoms on bulk h-BN and on various models of the h-BN/Rh(111) nanomesh. While Au binds only weakly to bulk h-BN and h-BN/Rh(111) at the ``wire'' configurations, the underlying Rh atoms in the ``pores'' modify considerably the electronic structure of h-BN and Au adsorbs strongly on top of the B atoms. The adsorption is accompanied by a strong outward relaxation of the B atoms and a significantly charging of the Au atoms [2].

Furthermore, we will present first results of the adsorption of small Au[n] clusters (n=2-4) in the ``pores''. Their adsorption properties show similar trends as observed for single Au atoms.

[1] M. Corso et al., Science 303: 217 (2004)

[2] HP. Koch et al., Phys. Rev. B in print