Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 80: Low-Dimensional Systems - Poster Session

TT 80.5: Poster

Mittwoch, 2. April 2014, 15:00–19:00, P2

Probing the eletronic structure of γ-Al₂O₃/SrTiO₃ oxide heterostructures by hard x-ray photoelectron spectroscopy — •Philipp Schütz¹, Florian Pfaff¹, Philipp Scheiderer¹, Götz Berner¹, Mihaela Gorgoi², Michael Sing¹, and Ralph Claessen¹ — ¹Physikalisches Institut and Röntgen Center for Complex Materials Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — ²Helmholtz Zentrum Berlin für Materialien und Energie (HZB-BESSY II), Albert-Einstein-Strasse 15, 12489 Berlin, Germany

The heterointerface between the band insulators γ-Al₂O₃ and SrTiO₃ hosts a two-dimensional electron system (2DES) with exceptionally high electron mobility. The promising spinel/perovskite complex oxide heterostructure has been studied by hard x-ray photoelectron spectroscopy with high interface sensitivity. A detailed core level and valence band analysis yields information about the electronic structure, including band bending and band alignment at the interface. Evidence for the two-dimensional nature of the conducting interface is obtained from the angle dependent chemically shifted Ti³⁺ 2p core level signal, which is generally attributed to Ti ions with electrons hosted in the Ti 3d shell. The 2DES is found to be strongly confined within several unit cells of SrTiO₃ in proximity to the interface, with sheet carrier densities in the range of 10⁻¹⁴ cm⁻².