Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 12: Symposium: Size-Selected Clusters at Surfaces I
(Invited Speakers: Karl-Heinz Meiwes-Broer, Heinz Hövel, Thorsten Bernhardt)
O 12.5: Vortrag
Montag, 25. Februar 2008, 15:30–15:45, MA 005
Counting electrons in quantum-well states of Au chains on an alumina thin film on NiAl — •Maria Veronica Ganduglia-Pirovano1, Niklas Nilius2, Veronika Brazdova1, Maria Kulawik2, Joachim Sauer1, and Hans-Joachim Freund2 — 1Institut für Chemie, Humboldt-Universität zu Berlin, Berlin, Germany — 2Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
Low-temperature STM measurements combined with DFT calculations are employed to study the adsorption of gold on alumina/NiAl(110). The binding of Au monomers involves breaking of an oxide Al-O bond below the adatom and stabilizing the hence under-coordinated O ion by forming a new bond to an Al atom in the NiAl. The adsorption implies negative charging of the adatom. The linear arrangement of favorable binding sites induces the self-organization of Au atoms into chains. Their electronic structure is described by a series of quantum well states (QWSs) that evolve from the s-dz2 orbitals of the single adatoms. The node structure of the QWSs can only be explained when considering the charge transfer through the thin alumina film into the Au adchains in the electron count.
[1] N. Nilius, M. V. Ganduglia-Pirovano, V. Brázdová, M. Kulawik, J. Sauer, and H-J. Freund, Phys. Rev. Lett. submitted.