Regensburg 2019 – wissenschaftliches Programm
O 44.6: Poster
Dienstag, 2. April 2019, 18:00–20:00, Poster D
Changing the Characteristic Critical Current in an STM Josephson Junction by Magnetic Adatoms — •Rika Simon1, Nils Bogdanoff1, Olof Peters1, 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
Atomic spins on superconducting surfaces introduce so called Yu-Shiba-Rusinov (YSR) states inside the superconducting gap as a fingerprint of magnetic interaction. Additionally, a renormalization of the local order parameter is predicted by theory, which is not directly reflected in the differential conductance spectra. In contrast, the order parameter can be determined directly in a Josephson junction by measuring its characteristic critical current. The use of a superconducting tip and substrate creates this SIS Josephson junction in a scanning tunneling microscope (STM). The atomic scale spatial resolution of the STM enables the measurement of the critical current on individual magnetic adatoms. A depletion in critical current can be observed on Fe adatoms on a Pb(110) surface .
Here, we present further work investigating the seemingly even greater changes in critical current caused by Mn adatoms on Pb(111) in voltage- and current-biased Josephson junctions.
 M. T. Randeria, B. E. Feldman, I. K. Drozdov, and A. Yazdani, Scanning Josephson spectroscopy on the atomic scale, Phys. Rev. B 93, 161115(R), 2016