Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 69: Emerging oxide semiconductors II (Focus session with DS)
HL 69.12: Vortrag
Mittwoch, 2. April 2014, 18:30–18:45, POT 081
Surface structure of metal oxides via classical and quantum mechanical rainbow scattering — •Marco Busch1, Eric Meyer1, Jan Seifert1, Helmut Winter1, Klaus Irmscher2, and Zbigniew Galazka2 — 1Humboldt-Universität zu Berlin, Institut für Physik, Newtonstrasse 15, D-12489 Berlin, Germany — 2Leibniz-Institut für Kristallzüchtung, Max-Born-Strasse 2, D-12489 Berlin, Germany
Fast light atoms and molecules with energies from 200 eV up to several tens of keV are grazingly scattered from clean and flat metal oxide surfaces. The angular distributions of projectiles scattered in the regime of axial surface channeling show intensity maxima, which can be described with the concept of the classical rainbow scattering and offer the determination of the interaction surface potential. However, for decreasing projectile energy one can observe Bragg peaks in the angular distributions, which can be interpreted within the framework of quantum mechanics only. As examples, we present investigations of the quantum scattering from the cleaved (100) surface of β-Ga2O3 single crystals, grown by the Czochralski method. The splittings of Bragg peaks and their intensity modulations were so far exploited to deduce information on the arrangement of atoms in the topmost surface layer. Furthermore, diffraction effects were present in the regime of surface channeling, where quantum scattering is considered for the motion parallel to the surface. For the thermal induced reconstruction of the (1120) and (0001) surface of Al2O3 we found also a preservation of the longitudinal coherence and observed Laue circles of higher orders.