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O: Fachverband Oberflächenphysik

O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)

O 27.30: Poster

Dienstag, 24. März 2009, 18:30–21:00, P2

Simulation of photoelectron diffraction at high kinetic energies — •Aimo Winkelmann1, Charles S. Fadley2,3, and Javier Garcia de Abajo41Max Planck Institut für Mikrostrukturphysik, Halle, Germany — 2Department of Physics, University of California Davis, Davis, CA 95616, USA — 3Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA — 4Instituto de Optica – CSIC, Serrano 121, 28006 Madrid, Spain

The theoretical modelling of x-ray photoelectron diffraction (XPD) with hard x-ray excitation of up to 20 keV energy is discussed using the dynamical theory of electron diffraction [1]. Via calculations for diamond and silicon it is demonstrated that the dynamical theory explains available current data for kinetic energies around 1 keV very well. The XPD patterns for energies above about 1 keV are dominated by Kikuchi bands which are created by the dynamical scattering of electrons from lattice planes. The origin of the intensity distribution in such bands is discussed from the point of view of atomic positions in the unit cell. The profiles and positions of the element-specific photoelectron Kikuchi bands are found to be sensitive to lattice distortions and the position of impurities or dopants with respect to lattice sites. These results thus suggest several future uses of such hard XPD for studies of the bulk structure of complex materials. The dynamical calculations are compared to results from a cluster model that is more often used to describe lower-energy XPD.
A. Winkelmann, C.S. Fadley, F.J. Garcia de Abajo
  New J. Phys. 10 (2008) 113002

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