Berlin 2018 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 7: Thin Film Properties: Structure, Morphology and Composition (XRD, TEM, XPS, SIMS, RBS, AFM, ...): Session I
DS 7.3: Vortrag
Montag, 12. März 2018, 15:30–15:45, H 2032
Ti valence mapping in LAO/STO with Resonant Soft X-ray Reflectometry — •Martin Zwiebler1, Emiliano Di Gennaro2, Jorge Enrique Hamann-Borrero4, Fabio Miletto Granozio2, Enrico Schierle3, Eugen Weschke3, Bernd Büchner4, George Sawatzky5, Robert Green5, and Jochen Geck1 — 1Institut fuer Festkörper- und Materialphysik Technische Universität Dresden, 01062 Dresden, Germany — 2CNR-SPIN and Dipartimento di Finica, Complesso Universitario di Monte S. Angelo, Via Cintia, 80126 Naples, Italy — 3Helmholtz-Zentrum Berlin, BESSY, Albert-Einstein-Str. 15, 12489 Berlin, Germany — 4University of British Columbia 6224 Agricultural Road Vancouver, B.C. V6T 1Z1 Canada — 5IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
The two dimensional electron gas (2DEG) at the LaAlO3/SrTiO3 heterointerface exhibits intriguing features, which are currently not well understood. When at least four UCs of LAO are deposited on a STO substrate, mobile electrons accumulate at interfacial Ti sites. In order to establish the underlying physics, it is essential to know the charge density distribution of the 2DEG around the interface. We performed X-ray reflectivity measurements at the Ti L2,3 edge to determine the Ti stoichiometry and the depth-dependent electron content at the interface with resolution at the atomic scale. We demonstrate that the electron distribution is strongly T-dependent and interacts strongly with the lattice degrees of freedom. From the polarization dependence of the reflectivity we gain new results on the anisotropy of orbital energies and valence orbital occupation.