Dresden 2006 – scientific programme

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O: Oberflächenphysik

O 48: Nanostructures IV

O 48.3: Talk

Friday, March 31, 2006, 11:45–12:00, WIL A317

Ordered cluster arrays on a graphite-Ir(111) moiré pattern — •Alpha NDiaye, Sebastian Bleikamp, and Thomas Michely — I. Physikalisches Institut (IA) RWTH Aachen 52056 Aachen

Perfectly ordered Ir-cluster arrays can be formed on a functionalised Ir(111) surface. The clusters are bound in a hexagonal lattice with a lattice constant of 26 Å. Their size distribution is narrow and the size can be tuned from 6 to 150 atoms. The clusters possess a surprising thermal stability. Clusters with an average size of 5 atoms are stable up to 450 K. At low clustersizes, different types of clusters can be distinguished.

Functionalisation of the Ir(111) surface is achieved through preparation of monolayer graphite sheets, which can be formed by pyrolysis of hydrocarbons. The superposition of the graphite and Ir(111) surface gives rise to the emergence of a √91×√91 R5.23^∘ moiré pattern. Ir clusters form, where threefold coordinated adsorption sites of the underlying Ir(111) lattice are in the center of the graphite honeycomb unit cells.