Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 49: Metal Substrates: Structure, Adsorption and Growth

O 49.1: Poster

Dienstag, 8. März 2016, 18:15–20:30, Poster E

On the microscopic structure of the Ag(441) surface — •Thorsten Wagner, Robert Zimmerleiter, Daniel Roman Fritz, and Peter Zeppenfeld — Johannes Kepler University Linz, Institute for Experimental Physics, Austria

Regularly stepped (vicinal) surfaces provide a convenient path to control the number of defects of a surface. They can be easily prepared by a slight miscut of a low index surface. In the case of an fcc(nn1) surface with small integer n it is even expected that the large number of steps will dominate the surface properties. Here we report on a study of the Ag(441) surface using a combination of scanning tunneling microscopy (STM) and high resolution electron diffraction (SPA-LEED). The STM data suggest a statistical distribution of the step width which can be described by a Γ-probability distribution. In fact, the steps are not randomly distributed but are interacting. The detailed statistical analysis of the images also reveals that the terraces are formed by an integer number of (331) building blocks whereas the actual steps are given by (551) microfacets. In order to compare the electron diffraction data to the real space information from the STM experiment, we carried out simulations of the reciprocal space maps (RSM) in the framework of the simple kinematic approximation. In the case of narrow, interacting steps one has to be cautious to carry out a correct interpretation of the experimental RSM based on the splitting of the rods and their tilt angle, only. Especially the latter is strongly influenced by the correct alignment of the sample.