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O: Fachverband Oberflächenphysik
O 21: Clean surfaces: Metals, semiconductors, oxides and insulators II
O 21.1: Vortrag
Montag, 14. März 2011, 17:15–17:30, WIL B122
A combined Frequency Modulation Dynamic Force Microscopy (FM-DFM) and Scanning Tunneling Microscopy (STM) Study of a SiO2/Ru(0001) Model System — •Christin Büchner, Leonid Lichtenstein, Lars Heinke, Markus Heyde, and Hans-Joachim Freund — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
Silica based support materials play an important role in catalysis. A stable and well characterized crystalline silica film can act as a model system for bulk silica and help us to understand silica’s properties in detail. In order to examine catalytically relevant processes on such model surfaces, a thorough investigation of defect sites of any form is eminent. Recently, a double-layer silica film could be prepared on Ru(0001).[1] Here we used a combined frequency modulation dynamic force microscope (FM-DFM) and scanning tunneling microscope (STM) under low temperature and ultra-high vacuum conditions to unveil the thin film’s structural and electronic surface properties. Atomically resolved images of the crystalline silica film grown on Ru(0001) are presented. Structural elements of the pristine film, as well as its defects, are highlighted. Based on atomic resolution FM-DFM and STM images a direct comparison with density functional theory calculation can be made. Theory as well as experiment favor a hexagonal honeycomb structure of the film. Spectroscopy measurements, i.e. scanning tunneling spectroscopy (STS) and Kelvin probe force microscopy (KPFM), provide first insights into electronic properties of the system. [1] Löffler et al., Phys. Rev. Lett. 105, 146194-1-4 (2010).