Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 31: Surface Magnetism / Magnetic Imaging II

MA 31.6: Talk

Thursday, March 25, 2010, 16:30–16:45, H23

Spin-polarized two-photon photoemission from Co/Cu(001) via unoccupied quantum well states — •Cheng-Tien Chiang, Aimo Winkelmann, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, Halle(Saale), Germany

We measured spin-resolved two-photon photoemission (2PPE) from ultrathin cobalt films grown on Cu(001). By using p-polarized light with 3.1 eV photon energy, we observed a dominant majority spin-polarization in 2PPE, extending from the initial states at 1.4 eV below the Fermi level up to the Fermi level. Moreover, we resolved an enhancement of spin-polarization by about 10% in 2PPE through the majority quantum well state in a 6 ML cobalt film. This is confirmed by a cobalt thickness dependent measurement. Comparison between spin-resolved one- and two-photon photoemission conveys the important role of the intermediate states in spin-dependent nonlinear photoemission.