Ordered array of single adatoms with remarkable thermal stability: Au/Fe3O4(001)

Z. Novotny, G. Argentero, Z. Wang, M. Schmid, U. Diebold, G. S. Parkinson

Institut für Angewandte Physik, Technische Universität Wien, 1040 Wien, Austria

Phys. Rev. Lett. 108 (2012) 216103

Gold deposited on the Fe3O4(001) surface was studied using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) at room temperature. This surface forms a (√2 × √2)R45° reconstruction, where pairs of Fe and neighboring O ions are slightly displaced laterally producing undulating rows with 'narrow' and 'wide' hollow sites. At low coverages, single Au adatoms adsorb exclusively at the narrow sites, with no significant sintering up to annealing temperatures of 400 °C. We propose the strong site preference to be related to charge and orbital ordering within the first subsurface layer of Fe3O4(001)-(√2 × √2)R45°. Due to its high thermal stability, this could prove an ideal model system for probing the chemical reactivity of single atomic species.

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Corresponding author: Gareth S. Parkinson (parkinson< encoded email address >).