Real-time view of single molecule motion with aberration corrected LEEM

• Applicant: Dr. Simon Sindermann
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2014 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 258095485

Self-Assembly of atoms and molecules on atomically-controlled surfaces provides a good possibility to fabricate nanostructures. The diffusion, i.e. the thermal activated motion of the atoms or molecules, plays an important role. In the past, the diffusion processes of atomic systems were studied in detail and now are well understood.For organic molecules, diffusion and self-assembly are more complicated. Due to the complex structure of some organic molecules, additional influences, e.g. charge transfer inside the molecules or spatial different binding energies, have to be considered. Scanning Tunneling Microscopy (STM) shows that Polyphenyl-Dicarbonitril molecules form different networks on metallic surfaces. In the point of intersection, the molecule orientation can vary significantly. Since the STM-studies are performed at low temperatures, after the self-assembly process is completed, the dynamics of the molecule motion during self-assembly cannot be monitored with this technique.The recent progress in aberration correction for Low Energy Electron Microscopy (LEEM), improves the resolution down to 1.4 nm, which is in the order of magnitude of the length of Polyphenyl-Dicarbonitril molecules. Single molecules, e.g. Sexiphenyl-Dicarbonitril with a length of 3 nm, and especially their orientation can now be monitored in LEEM at room temperature. Here the molecule motion during self-assembly of Sexiphenyl-Dicarbonitril on silver and copper surfaces shall be studied in real-time with emphasis on the molecule orientation and its influence to self-assembly and diffusion.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Rudolf Tromp