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.