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O: Fachverband Oberflächenphysik
O 49: Poster Session IV: Electronic structure of surfaces: Spectroscopy, surface states II
O 49.4: Poster
Tuesday, March 2, 2021, 13:30–15:30, P
Switching current distribution in a STM Josephson junction on a Pb(111) surface with Mn adatoms — •Martina Trahms1, David Wander2, J. Rika Simon1, Nils Bogdanoff1, Olof Peters1, Katharina Biel1, Gaël Reecht1, Clemens B. Winkelmann2, and Katharina J. Franke1 — 1Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — 2Univ. Grenoble Alpes, Institut Neél, 25 Avenue des Martyrs, 38042 Grenoble, France
Magnetic impurities on superconducting surfaces are expected to locally disturb the superconducting ground state. The critical current of a Josephson junction is a measure of the superconducting order parameter. We employ current-biased Josephson spectroscopy in a scanning tunneling microscope (STM) to measure the junction’s switching current which is directly related to the critical current and marks the transition from Cooper-pair tunneling to quasi-particle tunneling. To investigate the activation processes of the switching events, we statistically analyse the switching of a Josephson junction formed between a Pb tip and a Pb adatom on a Pb(111) surface. By adding Mn adatoms to the Pb surface, we show a local reduction of the switching current and thereby a disturbance of the local order parameter due to the magnetic interaction. Additionally, we probe the switching current distribution in close proximity to the Mn atoms.