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O: Fachverband Oberflächenphysik
O 45: Focus Session: Scanning Probe Microscopy with Quartz Sensors I
O 45.7: Talk
Wednesday, March 29, 2023, 12:15–12:30, CHE 89
Monitoring of molecular configurations in SPM-based molecular manipulation — Joshua Scheidt1, Alexander Diener1, Michael Maiworm2, Klaus-Robert Müller3, Rolf Findeisen2, Kurt Driessens4, F. Stefan Tautz1, and •Christian Wagner1 — 1Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Germany — 2Control and Cyber-Physical Systems Laboratory, Technische Universität Darmstadt, Germany — 3Machine Learning Group, Technische Universität Berlin, Germany — 4Data Science and Knowledge Engineering, Maastricht University, The Netherlands
Molecular manipulation with the SPM tip as an actuator allows creating a wide variety of molecular junction configurations. Unfortunately, the precise atomic locations in such a junction, which strongly impact its mechanical and electronic properties, cannot be observed directly. Here, we present and benchmark an approach that enables such a configuration monitoring. It overcomes the most important challenges: the need for accurate yet fast simulations, the disparity between scalar observation quantities like a force gradient and a high-dimensional unknown molecular configuration, the vast configuration space to be searched, and the need to operate on the few-minutes time scales of typical experiments. This is achieved by combining a finite state automaton to store and rapidly access the results of atomistic molecular simulations, and a particle filter to search for likely manipulation trajectories, given an input sequence of observations. We are able to assign systematic differences in generic features in force gradient data to well-defined atomic configurations for the first time.