Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 15: Postersitzung (Adsorption an Oberfl
ächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Rastersondentechniken, Zeitaufgelöste Spektroskopie, Methoden)

O 15.26: Poster

Freitag, 4. März 2005, 17:00–20:00, Poster TU D

X-ray Standing Wave Imaging: the Growth of the First Monolayer YBa₂Cu₃O_7−δ on SrTiO₃(001) — •Sebastian Thieß, Tien-Lin Lee, Bruce C.C. Cowie, and Jörg Zegenhagen — ESRF, Grenoble, France

For structure determination the X-ray Standing Wave (XSW) technique can be used as an element specific Fourier technique, which allows determining amplitude and phase of the Fourier coefficients of atomic distribution functions ρ(r). In order to obtain the (hkl)^th Fourier coefficient of ρ(r), the photoemission from a sample is recorded while the X-ray photon energy is simultaneously scanned through the energy range of the (hkl) Bragg reflection. A real space image of ρ(r) is rendered by back transforming a sufficient number of Fourier coefficients.

We have studied the nucleation of the first monolayer YBCO on the STO(001) surface. 3D Fourier reconstructed images show the crystallographic distribution of all constituent elements of a 1 ML and a 0.5 ML YBCO film grown in situ by pulsed laser deposition. XSW measurements were carried out in UHV at beamline ID32 at the ESRF for 7 different STO(hkl) reflections at photon energies between 2.7 and 5.5 keV.