Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Electronic Structure of Surfaces II

O 58.2: Vortrag

Mittwoch, 18. März 2015, 15:15–15:30, MA 041

Core-resonant double photoemission studies of S-overlayers — •Gianluca Di Filippo¹, Frank Oliver Schumann¹, Mario Italo Trioni², Guido Fratesi³, Zheng Wei¹, Chang-Hui Li¹, Lucie Behnke¹, Swapnil Patil¹, Giovanni Stefani⁴, and Jürgen Kirschner^1,5 — ¹Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany — ²CNR, ISTM, Milano, Italy — ³Università degli Studi di Milano Bicocca, Mlano, Italy — ⁴Università degli Studi Roma Tre, Roma, Italy — ⁵Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany

The power of core-resonant double photoemission (DPE), i.e. Auger decay, in determining the strength of electronic correlations in the valence band of solids is well established [1,2]. We employed this technique to investigate the properties of sulfur overlayers on metal substrates. We exposed a Cu(100), a oxygen passivated Cu(100) and a Ni(100) surface to H₂S gas. This caused the formation of S overlayers with nominal coverages of 0.25, 0.48 and 0.5 ML. We focused on the process in which the de-excitation of the S 2p level results in a doubly-ionized final state with two vacancies in the S/metal surface states. The measured DPE line shapes show small differences which are mainly ascribable to the variation of the density of states at the different surfaces. We determined the strength of the electron-electron interaction energy, which is hardly affected by coverage or substrate variations.