Dresden 2003 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
O: Oberflächenphysik
O 31: Organische Dünnschichten II
O 31.3: Vortrag
Donnerstag, 27. März 2003, 15:30–15:45, HSZ/02
2D Molecular Phase Transition in the Nanometer Scale Controlled by the Scanning Tunneling Microscope Tip — •Simon Berner1, Michael de Wild1, Luca Ramoino1, Silvia Schintke1, Alexis Baratoff1, Hans-Joachim Güntherodt1, and Thomas A. Jung2 — 1Institute of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland — 2Paul Scherrer Institute, CH-5232 Villigen, Switzerland
In this work we studied Sub-phthalocyanine (SubPc) layers with a coverage in the order of 0.7 monolayers on Ag(111) with room temperature scanning tunneling microscopy (STM). On large terraces the SubPc molecules form a hexagonal close packed (hcp) superstructure. However, experimental sequences on confined terrace areas (vacancy islands with diameters of 30-80 nm introduced by sputter defects) reveal interesting details about the condensation and evaporation of molecular islands on a nanometer scale. In such vacancy islands reversible phase transitions between 2D mobile and 2D condensed (hcp) phases could be controlled by the STM tip. In addition, rotational flipping of the orientation of condensed islands between two different substrate lattice registries occurred. Different microscopic mechanisms are discussed in the context of this newly observed complex behaviour.