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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 Kirschner1,5 — 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.
[2] G.A. Sawatzky, Phys. Rev. Lett., 39, 504 (1977)