Benetzungsstudien flüssiger Helium-Filme auf Alkalimetallen

• Applicant: Privatdozent Dr. Jürgen Klier
• Subject Area: Experimental Condensed Matter Physics
• Term: from 1998 to 2005
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5107992

The project deals with one of the weakest binding systems in condensed matter physics: liquid helium adsorbed on alkali metal surfaces. The helium-alkali binding is even weaker than the 4He-4He attraction, which leads to nonwetting of liquid 4He on Cs and Rb. These systems provide an ideal research area to study fundamental behaviour of wetting phenomena. The dynamics of the wetting and dewetting processes can be precisely investigated. However, discrepancies in the measured contact angles and observed hysteresis suggest that the morphology of the surface has a significant influence on the wetting behaviour. Therefore, central for this project, is the in situ characterisation of these surfaces and the correlation with their wetting properties. Excitations and 3He interface states between the Cs-surface and the liquid helium shall be thoroughly studied in order to understand the adsorbate/substrate interface. This is crucial to understand the observed wetting behaviour. Experiments have shown that also a phase transition should exist in the nonwetting 2-dimensional thin film. This phenomenon shall be investigated.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1052: Benetzung und Strukturbildung an Grenzflächen
• Participating Person: Professor Dr. Paul Leiderer