Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 53: Surface Nanopatterns
O 53.2: Vortrag
Mittwoch, 27. Februar 2008, 15:30–15:45, MA 043
Investigation of surface modifications induced by swift heavy ions in the MeV regime. Part II : Theory — •Orkhan Osmani1,2 and Marika Schleberger1 — 1Universität Duisburg-Essen, Fachbereich Physik, Lotharstrasse 1, 47048 Duisburg — 2TU Kaiserslautern, Fachbereich Physik, Gottlieb-Daimler-Straße, 67653 Kaiserslautern
In the last few years various experiments on ion-solid interactions have been performed. In a recent experiment structural chain like surface modifications with chain length up to some micrometers have been observed. These modifications are strongly dependent on the angle of incidence and believed to be created by local melting of the solid due to the energy transfer of the ion to the solid. An new model will be presented which is capable to describe the energy loss of a swift heavy ion penetrating an insulator like SrTi03 and the creation of the so called nanodots. At ion energies of several 10 MeV to 100 MeV the energy loss is due to electronic stopping only. To describe the electronic excitation induced bye the ion–electron interaction we use an approach taking the electronic density into account. Time and spatially resolved energy losses are calculated and used as sourceterms for the electrons within a Two–Temperature–Modell. Finally, the relaxation of the electrons by simultaneous phononic excitation leads to a phononic temperature distribution. In this way, it can be checked if the phononic temperature is above the melting temperature, thus leading to a thermal melting.