Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)
O 35.85: Poster
Dienstag, 27. März 2012, 18:15–21:45, Poster B
Surface and Image-Potential States of Ni(111) Investigated with Spin- and Time-Resolved 2PPE — Thomas Odebrecht1,2, •Beatrice Andres1,2, Marko Wietstruk1,2, Anke B. Schmidt3, Markus Donath3, and Martin Weinelt1,2 — 1Max-Born-Institut, 12489 Berlin — 2Fachbereich Physik, Freie Universität Berlin, 14195 Berlin — 3Physikalisches Institut, Westfälische Wilhelms-Universität Münster, 48149 Münster
The surface electronic structure of Ni(111) does not only exhibit occupied sp- and d-derived bulk states and surface resonances [1], but also a partially occupied Shockley-like surface state (SSS) as well as a Rydberg-series of image-potential states (IPS) close to the vacuum enegy. In two-photon photoemission experiments (2PPE) using the fundamental (1hν=1.6 eV) and the third harmonic (3hν = 4.8 eV) of our Ti:Sa laser, we gain information on exchange splitting, spin polarization and spin-dependent lifetimes of these states.
We can either populate the unoccupied minority component of the SSS with a 1hν pulse and probe with 3hν or use a 3hν-pump and 1hν-probe pulse to reach the energetic region of the IPS. Populating the IPS out of the occupied components of the surface and bulk states we create a spin-polarized population in these unoccupied states which allows us to study their spin-dependent properties.
[1] Okuda et. al., Phys. Rev. B 80, 180404 (2009).