Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 84: Scanning Probe Techniques: Method Developments
O 84.8: Vortrag
Donnerstag, 10. März 2016, 17:00–17:15, S054
A quantitative tool to measure nanoscale electrostatic potentials — •Matthew F. B. Green1,2, Christian Wagner1,2, Philipp Leinen1,2, Thorsten Deilmann3, Peter Krüger3, Michael Rohlfing3, Ruslan Temirov1,2, and F. Stefan Tautz1,2 — 1Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany — 2JARA - Fundamentals of Future Information Technology — 3Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster
Interactions between nanoscale objects on surfaces are dominated by the van der Waals and electrostatic contributions. The ability to characterize the electrostatic field on a surface would therefore be a valuable tool for many areas of nanoscience research. Recently we presented a technique called scanning quantum dot microscopy (SQDM), whereby local electrostatic potentials on surfaces can be measured quantitatively and in three dimensions. By registering the charging events of a single molecule weakly hybridized to an nc-AFM tip, acting as a QD, the quadrupole potential of a single molecule and the dipole potential of a single ad-atom were investigated. In addition we demonstrated the remarkable sensitivity of SQDM by probing an ad-atom from 6 nm away [1]. We now present a quantitative model of the charging dynamics based on single electron box theory [2], taking the orbital hybridization and junction geometry into account. By fitting the model to experimental data, we show how the system parameters affect the way that the charging manifests itself in the frequency shift signal.
[1] C. Wagner et al., Phys. Rev. Lett. 115, 026101 (2015)
[2] Nanoelectronics and Information Technology: Advanced Electronic Materials and Novel Devices, edited by R. Waser (John Wiley & Sons, New York, 2003), Chap. 16