Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 74: Nanostructures at surfaces: Other aspects
O 74.6: Vortrag
Mittwoch, 14. März 2018, 18:00–18:15, MA 141
Confined lattice dynamics in ultrathin Ge/Fe3Si/GaAs heterostructures — •Jochen Kalt1,2, Małgorzata Sternik3, Ilya Sergeev4, Bernd Jenichen5, Olaf Leupold4, Ramu Pradip1,2, Hans-Christian Wille4, Przemysław Piekarz3, Krzysztof Parlinski3, Tilo Baumbach1,2, Svetoslav Stankov1,2, and Jens Herfort5 — 11Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Karlsruhe, Germany — 22Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany — 3Institute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland — 4Deutsches Elektronen-Synchrotron, Hamburg, Germany — 5Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany
We studied the phonon properties of ultrathin 57Fe3Si layers in Ge/57Fe3Si/GaAs heterostructures as a model system for lattice dynamics modifications in metal/semiconductor interfaces. Epitaxial 57Fe3Si layers with thicknesses from 2ML to 36ML were grown on GaAs(001) substrates and capped by a 4 nm thick amorphous Ge layer. Sample characterization with various methods showed the formation of epitaxial Fe3Si nanostructures with perfect stoichiometry and high interface quality. Nuclear Inelastic Scattering was used to determine the iron-partial phonon density of states at room temperature as a function of layer thickness. While the phonon DOS of the 36 ML sample is fully reproduced by the ab initio calculated DOS of bulk Fe3Si, significant deviations are observed for lower interface thicknesses leading to anomalies in the thermoelastic properties.