Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 15: STM/AFM: New Approaches
O 15.11: Vortrag
Montag, 7. März 2016, 17:45–18:00, H24
Scanning quantum dot microscopy made faster — •Christian Wagner1,2, Michael Maiworm3, Christian Müller3, Matthew F. B. Green1,2, Philipp Leinen1,2, Eric Bullinger3, Rolf Findeisen3, F. Stefan Tautz1,2, and Ruslan Temirov1,2 — 1Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Germany — 2JARA-Fundamentals of Future Information Technology — 3Institute for Automation Engineering (IFAT), Otto-von-Guericke University Magdeburg, Germany
Scanning quantum dot microscopy (SQDM) is a novel NC-AFM based scanning probe method that allows for the measurement of electric potentials with high sensitivity and spatial resolution[1]. To record SQDM images a single organic molecule is attached to the probe tip. This sensor molecule works as a quantum dot that can be charged via tunneling to or from the tip, depending on the local electrostatic potential. In a Δ f(V) spectrum the charging event causes a sharp dip, the position of which is the actual quantity of interest. The sharpness of this dip (≈ 30 meV) suggests that methods beyond Δ f(V) spectroscopy could be used to measure its position, allowing image acquisition time to decrease from hours to minutes, making the method more versatile and easy to use. We discuss an approach to this task that is based on concepts from control theory such as system identification and extremum seeking controller.
[1] C. Wagner, M.F.B. Green, P. Leinen, T. Deilmann, P. Krüger, M. Rohlfing, R. Temirov, and F.S. Tautz, Phys. Rev. Lett. 115, 026101 (2015).