Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 80: Poster: Scanning Probe Techniques - Method Development
O 80.20: Poster
Mittwoch, 14. März 2018, 18:15–20:30, Poster A
Towards a radio frequency four tip scanning tunneling microscope — •Jonas Duffhauß1, Marco Pratzer1, Vasily Cherepanov2, Bert Voigtländer2, and Markus Morgenstern1 — 1RWTH Aachen University/JARA-Fit — 2Jülich Research Center
A four tip STM [1] has been modified with different cablings that allow for STM measurements in the GHz regime. The time resolution has been determined by a pump-probe experiment using a sample with a non-linear dI/dV characteristic (Gold, HOPG) [2].
A time resolution of < 180 ps was demonstrated if a RF-cable is used as tip, which is likely limited by the voltage pulse generator. Using the four tip STM with the already implemented tip exchange mechanism, the time resolution gets worse (≈ 350 ps) due to the additional impedance missmatch. Ringing effects caused by standing waves inside the cable and a low transmission at high frequencies (10 GHz) are identified as main cause for the reduced time resolution.
Options for further improvements of the RF parts, e.g., a low noise bias-tee, are discussed.
[1] V. Cherepanov, E. Zubkov, H. Junker, S. Korte, M. Blab, P. Coenen, and B. Voigtländer, Rev. Sci. Instr., 83, 033707 (2012).
[2] C. Saunus, J. R. Bindel, M. Pratzer, and M. Morgenstern, Appl. Phys. Lett. 102, 051601 (2013).