Seminar: Sensing the Quantum Limits in Scanning Tunneling Spectroscopy
- Location: Ångströmlaboratoriet, Lägerhyddsvägen 1 Å80121
- Lecturer: Christian Ast, MPI-FKF Stuttgart
- Contact person: Annica Black-Schaffer
Despite plenty of room at the bottom, there is a limit to the miniaturization of every process. For charge transport this is realized by the coupling of single discrete energy levels at the atomic scale. Here, we demonstrate sequential tunneling between parity protected Yu-Shiba-Rusinov (YSR) states bound to magnetic impurities located on the superconducting tip and sample of a scanning tunneling microscope at 10 mK. We reduce the relaxation of the excited YSR state to the bare minimum and find an enhanced lifetime for single quasiparticle levels. This provides interesting perspectives for manipulating these states via current pulses as well as with microwaves via a pump-probe mechanism. Our work offers a way to characterize and to manipulate coupled superconducting bound states, such as Andreev levels, YSR states, or Majorana bound states.