Regensburg 2002 – wissenschaftliches Programm
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M: Metallphysik
M 9: Quasikristalle II
M 9.3: Fachvortrag
Dienstag, 12. März 2002, 12:00–12:15, H6
Surfaces of Quasicrystalls: Morphology, Epitaxy, and Phase Transitions — •W. Theis1, J. K. Franke1, P. Kury2, M. Horn-von Hoegen2, P. Gille3, P. Ebert4, and K. H. Rieder1 — 1Institut fr Experimentalphysik der Freien Universität Berlin — 2Institut für Laser- und Plasmaphysik, Universität GH Essen — 3Institut für Kristallographie der Ludwig-Maximilians-Universität München — 4Institut fr Festkörperphysik, Forschungszentrum Jülich
While the basic bulk properties of quasicrystals are well understood, many fundamental questions regarding their surfaces are still unresolved. A major obstacle is the necessity to do experiment on surfaces close to their thermodynamic equilibrium. As the surface preparation involves ion bombardment requiring subsequent annealing it is difficult to judge whether the surface is still close to the equilibrium after the sample has cooled to room temperature, at which many experiments are performed.
In order to study near-equilibrium surfaces and learn how well the room temperature surfaces are suited to gain a general understanding of quasicrystalline surfaces we performed low energy electron microscopy (LEEM) from AlNiCo and AlPdMn low index surfaces at temperatures up to 850C. Flat steps and terraces at high temperatures, surface phase transitions and major changes in surface morphology linked to bulk phase transitions, as well as the formation and desorption of a quasicrystalline epitaxial layer were observed and will be reported.