Regensburg 2013 – scientific programme

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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Organic films and electronics, photoorganics; Nanostructures; Plasmonics and nanooptics, Surface chemical reactions and heterogeneous catalysis, Surface dynamics )

O 36.60: Poster

Tuesday, March 12, 2013, 18:15–21:45, Poster B2

Quantum-Well-States with non-vanishing momentum component in Cu/Co/Cu(100)-Systems — Philipp Kloth, Martin Wenderoth, •Philip Willke, Henning Prüser, and Rainer G. Ulbrich — IV. Phys. Inst., Georg-August-Universität, Göttingen

Quantum-well-states can form in metallic heterostructures and have been investigated by several methods, for example photoemission [1] and STM [2]. We report the formation of quantum-well-states above the Fermi energy for a Cu/Co/Cu(100)-layer system using low-temperature scanning tunneling spectroscopy. These states emerge from a stationary point at the Fermi surface with a non-zero parallel momentum component. We show that the preparation method of the metallic heterostructures is a crucial parameter for the formation of these states. By comparing our results with a transfer matrix simulation in combination with a tight-binding band structure calculation, a cross-over between resonance states and bound states can be identified. This results in a phase shift of the energetic dispersion of these states with varying the confinement thickness. Furthermore, these states seem to dominate the density of states of copper compared to the more prominent well-states in this system with no parallel wave vector component.

We acknowledge the financial support by the DFG SFB 602 Project A3.

[1] J.E. Ortega, F.J. Himpsel, G.J. Mankey, and R.F. Willis, Phys. Rev. B 47, 1540-1552 (1993)

[2] M. Becker and R. Berndt, Phys. Rev. B 81, 205438 (2010)