Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 12: Nanostructures at Surfaces II (Wires, Tubes)

O 12.5: Talk

Monday, March 26, 2007, 15:15–15:30, H36

Pt Nanowires on Ge(001): A Real- and K-Space Investigation — •Marc Wisniewski, Jörg Schäfer, Florian Sandrock, and Ralph Claessen — Universität, Würzburg, Germany

Electron confinement to one dimension is expected to reveal new phenomena due to the reduced electronic degrees of freedom. The possibility of charge density waves or a potential collapse of the Fermi liquid picture are key scenarios associated with such conditions. A highly one-dimensional model system is thus most desirable. In this respect, a number of quasi-one-dimensional metallic reconstructions on semiconductors, so-called nanowires, have been identified in the last years. A little explored class of noble metal nanowires are formed by self-organized platinum chains on the Ge(001) surface. These wires have a diameter of only one atom on their top, thereby representing single-atom chains. For clarifying their real space structure, scanning tunneling microscopy was performed at very low voltages and currents. In fact, the nanowires can be imaged in the millivolt regime, suggestive of a metallic behavior. A dimerization is seen at high tunneling bias. The various dimers are indicative of building blocks in the embankment, rather than a charge density wave. To obtain further evidence on the electronic properties near the Fermi level, angle-resolved photoemission studies are currently underway. A report on the key features of the electronic strucutre will be presented.