Tunneling Processes into Localized Subgap States in Superconductors.
We combine scanning-tunneling-spectroscopy experiments probing magnetic impurities on a superconducting surface with a theoretical analysis of the tunneling processes between (superconducting) tip and substrate. We show that the current through impurity-induced Shiba bound states is carried by single-electron tunneling at large tip-substrate distances and Andreev reflections at smaller distances. The single-electron current requires relaxation processes, allowing us to extract information on quasiparticle transitions and lifetimes.
Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
Michael
M
Ruby
Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
Falko
F
Pientka
Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
Yang
Y
Peng
Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
Felix
F
von Oppen
Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
Benjamin W
BW
Heinrich
Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
Katharina J
KJ
Franke