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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.22: Poster
Wednesday, March 16, 2011, 17:30–21:00, P4
Electron pair emission from NiO(100) — •Changhui Li, Lucie Behnke, Frank O. Schumann, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
The study of electron pair emission from surface upon electron or photon impact allows to study the electron-electron correlation, which plays an important role to determine the electronic and magnetic properties of materials, especially for strongly correlated systems. We present a first electron pair emission study from a strongly correlated system, namely NiO. We have grown ultrathin NiO(100) films on Ag(100) following standard procedures. We excite the sample with a primary electron beam in the energy range energies (Ep=35-85 eV). Compared with Ag, the coincidence count rate of NiO is about 7 times larger and the secondary electrons make much larger contributions in the electron pair emission. The sum energy spectra of the pairs shows structure which we can relate to the valence band structure. The way the available energy is shared among the electrons depends strongly on the primary energy. For Ep in the range 35-54 eV, the electrons prefer unequal energy sharing, whereas equal energy sharing is adopted for higher primary energies.