Oktober 2009


Best Poster Prize for Stefan Hellmann and Timm Rohwer

At the workshop on Ultrafast x-ray methods for studying transient electronic structure and nuclear dynamics Stefan Hellmann (AG Kipp) and Timm Rohwer (AG Bauer) were awarded the best poster prize, which is comprised of a certificate and prize money. 

In their poster entitled "Ultrafast photoelectron spectroscopy using FEL and HHG" the two PhD students presented femtosecond time-resolved photoemission data monitoring the temporal evolution of a phase transition in the model compound TaS2. The experiments have been performed at the Free Electron Laser (FEL) facility in Hamburg and at a laser-based pulsed soft X-ray source in Kiel. The results particularly demonstrate the large potential of state-of-the-art femtosecond light sources to provide new insights into the ultrafast physics in solid state systems.

Stefan Hellmann and Timm Rohwer are working in a close cooperation of the Kipp and Bauer group on time-resolved photoelectron spectroscopy with femtosecond (10-15 s) resolution. The workshop, which took place at the Physikzentrum Bad Honnef, 28 September - 1 October 2009, was organized by Dr. Philippe Wernet (Helmholtz Zentrum Berlin) and Prof. Dr. Matias Bargheer (Universität Potsdam) and supported by the Wilhelm und Else Heraeus Foundation. I t brought together a group of 73 scientists from Europe, the US and Japan, who are working on various methods of using upcoming ultrafast X-ray sources for condensed matter physics.

European researchers have measured the electrical conductance between a single pair of precisely oriented C60 molecules. In the 6 November Physical Review Letters    they describe picking up one molecule on the tip of an ultrafine scanning-tunneling-microscope probe and monitoring the current when it is positioned over another C60 molecule.