Dresden 2017 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 21: Functional Materials II

MM 21.1: Vortrag

Montag, 20. März 2017, 17:15–17:30, IFW D

Hydrogen induced defects in the palladium/rutile titanium dioxide model system — •Marian David Bongers¹, Mohsen Sotoudeh², Vladimir Roddatis¹, Jakub Čížek³, Carsten Nowak¹, Martin Wenderoth⁴, Peter Blöchl², and Astrid Pundt¹ — ¹Institut für Materialphysik, Univ. Göttingen — ²Institute for Theoretical Physics, Clausthal Univ. of Technology — ³Department of Low-temperature Physics, Charles Univ. in Prague, Czech Republic — ⁴IV. Physikalischen Institut, Univ. Göttingen

The palladium (Pd)/titanium dioxide (TiO₂) system is used in a range of applications where in particular the interaction with hydrogen (H) is of interest. We use in-situ transmission electron microscopy (ETEM) and electron energy loss spectroscopy (EELS) on cross-sectional Pd/TiO₂ lamella focusing on the interface. The EELS studies show a small change of the Ti L edge signal in the 3 nm close vicinity of the interface, for hydrogen gas pressures of about 10⁻¹ mbar. These small changes can be attributed to a shift in the density of states (DoS) by about 1 eV, by the presence of hydrogen. This is supported by projector augmented wave (PAW) code simulations using the local hybrid density functional PBE0r [1]. We suggest interstitial hydrogen to be the dominant hydrogen induced defect in bulk, while it is the oxygen-vacancy filled with hydrogen nearby the interface. These defects determine the corresponding Fermi level position in bulk and at the interface. This work is supported by the Deutsche Forschungsgemeinschaft via SFB1073, project C06 and C03 as well via the Heisenberg grant PU131/9-2. [1] M. Sotoudeh, M. Bongers, et al., submitted