Dresden 2009 – wissenschaftliches Programm
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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 Abajo4 — 1Max 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