Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 45: Oxides and insulators: Adsorption II

O 45.7: Vortrag

Mittwoch, 16. März 2011, 12:45–13:00, WIL C307

Adsorption of Au and Pd on a hematite surface — •Adam Kiejna and Tomasz Pabisiak — Institute of Experimental Physics, University of Wrocław, Wrocław, Poland

The adsorption of sumonolayer Au and Pd atoms at the two most stable (0001) surfaces of hematite, one being terminated by oxygen and the other by iron, is studied by spin-density functional theory. The changes in configuration caused by adsorption and the adsorption energy in different sites and for different Au and Pd coverages are investigated. The results show that both Au and Pd bind strongly to hematite surfaces and induce large changes in their geometry. In most stable Au and Pd adsorption sites the adsorbate atoms form threefold bonds with surface oxygen atoms. The binding is stronger for Pd than Au and for both adsorbates is distinctly stronger at the oxygen- than at the iron-terminated surface. The adsorbate interactions with substrate iron and oxygen atoms and their contributions to bonding are discussed based on the calculated local density of states and the electron charge transfer. The effect of on-site Coulomb interactions is briefly discussed based on the calculations performed within DFT+U scheme.