Two-dimensional ir cluster lattice on a graphene moiré on ir(111)
N'Diaye, Alpha1; Plasa, Tim1; Myslivecek, Josef1; Feibelman, Peter J.2; Michely, Thomas1 1Germany; 2United States
Lattices of Ir clusters have been grown by vapor phase deposition on graphene moirés on Ir(111). The clusters are highly ordered, and spatially and thermally stable below 500 K. Their narrow size distribution is tunable from 4 to about 130 atoms. A model for cluster binding to the graphene is presented based on scanning tunneling microscopy and density functional theory. The proposed binding mechanism suggests that similar cluster lattices might be grown of materials other than Ir. We investigated the average cluster size and the occupation probability of moiré cells as a function of coverage, temperature and annealing time. Assuming monomer and dimer mobility only, the data for temperatures up to 400 K may be reproduced fairly well by a simple kinetic Monte Carlo simulation.