Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 58: Electronic Structure of Surfaces II
O 58.4: Talk
Wednesday, March 18, 2015, 15:45–16:00, MA 041
Photon-energy dependent double photoemission spectroscopy from transition metal oxides — •Andreas Trützschler1,2, Cheng-Tien Chiang1,2, Michael Huth1, Frank O. Schumann1, Jürgen Kirschner1,2, and Wolf Widdra2,1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120, Halle(Saale), Germany — 2Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, D-06120, Halle(Saale), Germany
In the double photoemission (DPE) process, the excitation by a single photon leads to the emission of a pair of photoelectrons. The corresponding transition probability is closely related to the strength of electron correlation in the material [1]. In this contribution we report on DPE experiments on weakly correlated Ag(100) and strong correlated NiO(100) and CoO(100) surfaces [2]. By using a high-order harmonic generation light source at MHz repetition rates in combination with two time-of-flight spectrometers, we are able to compare single and double photoemission propabilities for these materials at different photon energies from 15 to 30 eV. At all photon energies, the ratio between single and double photoemission probability is significantly higher for NiO(100) and CoO(100) as compared to Ag(100), reaching about a factor of 4 at 30 eV photon energy.
[1] Berakdar, Phys. Rev. B 58, 9808 (1998)
[2] Huth, Chiang, Trützschler, Schumann, Kirschner, Widdra, Appl. Phys. Lett. 104, 061602 (2014)