Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 71: Metal substrates: Epitaxy and growth
O 71.3: Talk
Thursday, March 25, 2010, 15:30–15:45, H31
Structural analysis of Ag growth on Ni(111) — •Axel Meyer1, Jan Ingo Flege1, Sanjaya Senanayake2, Faisal Alamgir3, and Jens Falta1 — 1Institute of Solid State Physics, University of Bremen, 28359 Bremen, Germany — 2Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA — 3Georgia Institute of Technology, Atlanta, GA 30332-0245, USA
The growth structure and morphology of ultra-thin metal films on metallic substrates strongly influence the physical and chemical properties of the resulting bimetallic system. Therefore, a particular knowledge of these properties is crucial for creating functional materials with novel characteristics. In this contribution, a detailed study of the growth of ultra-thin silver films on the Ni(111) surface employing in-situ low-energy electron microscopy and diffraction (LEEM/LEED) is presented.
In the entire temperature range from 470 K to 850 K, silver is observed to grow in a Stranski-Krastanov mode with a wetting layer exhibiting a critical thickness of two atomic layers. For lower temperatures, the Ag films take on a collinear (7×7) structure or a 1∘ tilted (√57×√57)R6.59∘ structure, respectively, the latter as predicted by Chambon et al. (Phys. Rev. B 79 125412 (2009)). Elevated temperatures over 675 K lead to a (√52×√52)R13.9∘ reconstruction with extended rotational domains on the Ni(111) surface, while Ag/Ni intermixing is not observed throughout the whole temperature range. Furthermore, by quantitative intensity-voltage analysis of the specular beam, layer-dependent surface relaxations were determined.