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TT: Fachverband Tiefe Temperaturen
TT 18: Superconductivity: Poster
TT 18.24: Poster
Montag, 18. März 2024, 15:00–18:00, Poster C
UHV cleaving of superconducting Nb tips for scanning tunneling microscopy — Carolina A. Marques1, Aleš Cahlík1, Berk Zengin1, Tohru Kurosawa2, and •Fabian D. Natterer1 — 1Department of Physics, University of Zurich, Switzerland — 2Department of Applied Sciences, Muroran Institute of Technology, Japan
In scanning tunneling microscopy (STM), superconducting tips have been widely used because they enhance energy resolution, allow the study of Josephson tunneling, and provide an easy way to characterize and optimize the noise and energy resolution of a low-temperature experimental setup. In this work, we revisit the cleaving of superconducting wires in UHV and describe a one-step in-situ procedure to produce Nb tips with a well-resolved superconducting gap. We measure the superconducting gap of the Nb tip on Au(111) to prove the quality of the tips. Using a fully gapped tip, we optimize the RF filtering of our STM and determine its base temperature. We show that after coating the Nb tip with Au, suppressing the superconducting gap, the gap can be gradually recovered by sputtering with Ar+ ions, allowing the tuning of the gap size.
Keywords: Superconductivity; Scanning tunneling microscopy; Scanning tunneling spectroscopy; Superconducting tip; Gap function