Berlin 2008 – scientific programme

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DS: Fachverband Dünne Schichten

DS 17: Poster: Trends in Ion Beam Technology, Magnetism in Thin Films, Functional Oxides, High-k Dielectric Materials, Semiconductor Nanophotonics, Nanoengineered Thin Films, Layer Deposition Processes, Layer Growth, Layer Properties, Thin Film Characterisation, Metal and Amorphous Layers, Application of Thin Films

DS 17.35: Poster

Tuesday, February 26, 2008, 09:30–13:30, Poster A

INFRARED ELLIPSOMETRY STUDY OF LaNiO₃/LaAlO₃ SUPERLATTICES — •Y. Matiks, A.V. Boris, P. Popovich, H.-J. Kim, G. Cristiani, H.-U. Habermeier, and B. Keimer — Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart

The far-IR variable angle spectroscopic ellipsometry, as a power optical technique for the investigation of the dielectric properties of thin films, was used to study electrodynamics of LaNiO₃/LaAlO₃ superlattices. These superlattices with different individual layer thickness and number of interfaces were deposited on SrTiO₃, LaSrGaO₄, LaSrAlO₄ substrates by pulsed laser deposition.

We found that an increasing of substrate lattice parameter and a decreasing of individual layer thickness induce the decreasing of the charge carrier density. A decreasing of the thickness of layer to one unit cell leads to the insulator-metal transition in (LaNiO₃)n/(LaAlO₃)n superlattices on SrTiO₃ substrate. This metal-insulator transition may be induced by two factors: 1) localization of the electrons in the context of orbital reconstruction at the interfaces; 2) granulating of layers with the thickness close to one unit cell due to the roughness of substrates.