Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 26: Oxides and insulators: Clean surfaces
O 26.7: Vortrag
Dienstag, 23. März 2010, 12:00–12:15, H40
Temperature stabilised surface reconstructions at polar ZnO(0001) — •Mira Todorova1, Markus Valtiner2, Guido Grundmeier2,3, and Jörg Neugebauer1 — 1Department for Computational Materials Design, Max-Planck-Insitut für Eisenforschung GmbH, Düsseldorf — 2Christian Doppler Laboratory for Polymer/Metal Interfaces, Max-Planck-Insitut für Eisenforschung GmbH, Düsseldorf — 3Technical and Macromolecular Chemistry, University of Paderborn, Paderborn
Combining diffraction experiments with density-functional theory calculations and thermodynamic considerations we study the atomic structure of the polar ZnO(0001) surfaces. We show that a large number of very different reconstructions with similar stoichiometry are energetically almost degenerate, thus surface vibrational entropy contributions significantly affect their stabilisation. The large impact of the vibrational entropy on the surface structure gives rise to a strong dependence of surface phase diagrams on temperature and enables us to consistently describe and explain the experimentally observed surface structures on polar ZnO(0001) surfaces.
M. Valtiner, M. Todorova, G. Grundmeier, and J. Neugebauer, Phys. Rev. Lett. 103, 065502 (2009).