Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 3: Oxides and insulators I

O 3.5: Vortrag

Montag, 23. März 2009, 12:15–12:30, SCH A01

Investigation of ultra-thin Chromium layers on Titanium Dioxide by resonant photoemission — •Sebastian Müller and Dieter Schmeißer — Brandenburgische Technische Universität Cottbus, Konrad-Wachsmann-Allee 17, 03046 Cottbus

Oxide supported metal films and clusters offer interesting properties with a wide range of possible applications. In this context, Titanium Dioxide is chosen as a model substrate due to its simple electronic structure with a d⁰ configuration. We study the interaction of ultrathin Chromium films deposited on TiO₂ film with focus on the modifications of the valence band and band gap region. Normal photoemission in bulk and surface sensitive modes as well as resonant photoemission at the Cr 2p and Ti 2p edges are used to distinguish the different Cr 3d and Ti 3d contributions to the valence band. In the initial step we find to gap states of distinct character with a sharp resonance of the Cr 3d related state at the Cr 2p edge. With increasing layer thickness we observe that this resonance extends to about 20 eV below the Fermi-Energy. Datasets of valence band spectra measured around the Cr 2p edge show 2 resonant mechanisms in this case i.e. a participator channel for the 3d state accompanied by a spectator channel at fixed kinetic energy.