Berlin 2012 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 28: Thin film characterization: structure analysis and composition (Spectroscopy)
DS 28.4: Vortrag
Mittwoch, 28. März 2012, 18:30–18:45, H 2032
Direct Fourier imaging of distortions in LaAlO3 Films — •Christoph Schlueter1, Tien-Lin Lee2, Carmela Aruta3, and Jörg Zegenhagen1 — 1ESRF,Grenoble, France — 2Diamond Light Source Ltd, Didcot, UK — 3CNR-SPIN, Naples, Italy
The formation of a quasi-2dimensional electron gas at interface of SrTiO3 (STO) and LaAlO3 (LAO) attracted considerable attention in the recent years. The polar LAO layer was expected to cause the build-up of an electric potential. Distortions in the overlayer are discussed as one possible response of the system. The highly sensitive X-ray standing wave (XSW) imaging technique is well suited to study theses films because of its chemical and spacial resolution.
LAO thin films below (2uc) and above (6uc) the critical thickness for conductivity were studied at the hard X-ray photo electron spectroscopy end station of ID32 at the ESRF. The XSW modulated core level photo electron yield was recorded for the five elements present in film and substrate for seven different Bragg reflections. Subsequent analysis provided for each reflection and element the amplitude and phase of one Fourier coefficient of the elemental atomic distribution function. The three dimensional real space image of the atomic distribution for each of the elements is reconstructed by direct Fourier inversion. The reconstructed 3D images obtained by this model free approach reveal significant atomic displacements.