Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 39: Nanostructures III
O 39.4: Vortrag
Donnerstag, 30. März 2006, 15:45–16:00, PHY C213
Spin-polarized unoccupied states in Cu/Co/Cu(001) and Cu/Ni/Cu(001) thin-film structures — •Volker Renken1, Dehong Yu2, Georgi Rangelov1, and Markus Donath1 — 1Physics Institute, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany — 2Bragg Institute, Australian Nuclear Science and Technology Organisation, PMB 1, Menai NSW 2234, Australia
Ultrathin Cu films on thin fcc Co and Ni films grown on Cu(001) have been investigated by spin- and angle-resolved inverse photoemission. For no Cu overlayers but for increasing Co [1] and Ni film thickness on Cu(001), spin-polarized quantum-well states shift to higher energies and finally converge toward the lower band-gap boundary at the top of the sp-band. With little Cu overlayer coverage, the quantum-well states within the Co and Ni layers are still observed. With increasing Cu overlayer thickness, spin-polarized quantum-well states within the Cu layers are identified and eventually the Cu bulk sp-band is formed. Because the top of the sp-band is lower in energy for Cu compared to Co and Ni, a seemingly negative dispersion of the observed features with increasing Cu overlayer thickness appears. As a function of the electron momentum parallel to the surface, the quantum-well states develop into a surface resonance [2]. The loss of spin polarization of this surface resonance as a function of the Cu overlayer thickness reflects the penetration depth of the electron wave function.
[1] D.H. Yu et al., Phys. Rev. B 68 (2003) 155415,
[2] D.H. Yu and M. Donath, Europhys. Lett. 63 (2003) 729.