Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 29: Nanostructures at surfaces: preparation
O 29.4: Vortrag
Mittwoch, 25. März 2009, 11:15–11:30, SCH A01
Heat transfer in swift heavy ion irradiated Insulators — •Orkhan Osmani1,2, Marika Schleberger1, and Bärbel Rethfeld2 — 1Universität Duisburg-Essen, Fachbereich Physik, 47057 Duisburg — 2Technische Universität Kaiserslautern, Fachbereich Physik, 67653 Kaiserslautern
After irradiation of insulators of the perovskite type with an MeV ion beam under glancing incidents periodic nano patters on the surface can be observed [1]. To interpret the experimental data ab initio assisted calculations for the model system 100 MeV Xe → SrTiO3 have been performed [2]. For this system the electronic energy loss is calculated and used to compute the electronic excitation induced by the primary ion. The heat transport into the lattice away from the track core is performed in terms a two temperature model (TTM), a coupled system of diffusion equations. The heat transport is governed by a diffusivity parameter which is usually treated as a constant. However in the case of an insulator this is not appropriate. Therefore, a temperature dependent diffusivity is introduced, resulting in locally molten areas which agree well with the experimentally observed nano patterns. It will be shown that with a temperature dependent diffusivity, the TTM solution is no longer unique and is strongly depending on the spatial discretization chosen for the modeling [3].
[1] Nature Nanotechnology 2, 290-294 (2007)
[2] Journal of Physics: Condensed Matter 20, 315001 (2008)
[3] Laser and Particle Beams (Submitted)