Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 3: Scanning Probe Techniques: Method Development I
O 3.8: Vortrag
Montag, 20. März 2017, 12:15–12:30, TRE Phy
Characterization and variation of a single molecule-metal bond via AFM-based manipulation — •Philipp Leinen1,2, Matthew F. B. Green1,2, Christian Wagner1,2, Ruslan Temirov1,2, and F. Stefan Tautz1,2 — 1Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Germany — 2JARA-Fundamentals of Future Information Technology
Mechanical manipulation of molecules with the scanning probe microscope (SPM) is a versatile technique to study single-molecule properties and create new devices. A single bond established between the SPM tip and a reactive atom within the molecule is a very precise way to apply forces in such a manipulation and its understanding is therefore crucial. We studied the prototypical bond between carboxylic oxygen atoms of perylene-tetracarboxylic dianhydride (PTCDA) and the Ag terminated tip of a non-contact AFM/STM regarding its mechanical properties as well as the deformation the molecule undergoes during contacting and slight tip retraction. We focus on molecules within a layer which are retained by their neighbors, thus facilitating controlled tip-molecule bond breaking by mechanical stress alone. The bond forming and breaking also provides a sensitive probe to study the balance between intra- and intermolecular interactions. For the two inequivalent molecules in the unit cell of PTCDA/Ag(111) we observe that the tip height at which the bond to chemically identical oxygen atoms is established varies by 0.4 Å depending on the local environment of each oxygen in the monolayer. The data thus provides a sensitive benchmark for theory beyond just adsorption energy and height.