We investigate the fundamental properties of single atoms and molecules on solid surfaces. Within this field we are specifically interested in the growth of ultrathin insulating films, the manipulation and buildup of atomic-scale nanostructures, and the mechanical and electrical properties of individual molecules.
Our experiments exploit the extreme versatility and sensitivity of a low-(variable)-temperature scanning tunneling microscope / atomic force microscope (STM/AFM). Such a machine is not only a nanoanalytical instrument to perform imaging and vibrational/electronic spectroscopy on the atomic scale, but can also be used as an atomic-scale tool to assemble atomic structures, manipulate molecules and their conformations, and induce chemical reactions including the synthesis and dissociation (forming and breaking bonds) of individual molecules.
Overview of basic manipulation processes that can be induced with an STM
- Lateral manipulation: The transfer of atoms/molecules along the surface employing for example attractive/repulsive forces between the tip and the adsorbate.
- Vertical manipulation: The reversible transfer of atoms/molecules between the surface and the STM tip employing additionally electronic/vibrational excitation of the adsorbate by inelastic tunneling.
- Desorption: Similar to vertical manipulation, but desorption of individual adsorbates directly into the surrounding gas phase.
- Dissociation: Selective bond breaking within a molecule by means of inelastic tunneling processes.
- Synthesis: Selective bond formation between two molecular units employing lateral manipulation followed by electronic/vibrational excitation.