Freiburg 2019 – wissenschaftliches Programm

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FM: Fall Meeting

FM 59: Enabling Technologies: Quantum Dots and Superconductivity-based Systems

FM 59.3: Talk

Mittwoch, 25. September 2019, 14:30–14:45, 3043

Sensing the quantum limit in scanning tunneling microscopy: tunneling between single quasiparticle levels at atomic scale — •Haonan Huang¹, Jacob Senkpiel¹, Robert Drost¹, Ciprian Padurariu², Simon Dambach², Björn Kubala², Juan Carlos Cuevas³, Alfredo Levy Yeyati³, Joachim Ankerhold², Christian R. Ast¹, and Klaus Kern^1,4 — ¹MPI für Festkörperforschung, Germany — ²Institut für komplexe Quantensysteme, Universität Ulm, Germany — ³Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Spain — ⁴EPFL, Switzerland

Tunneling processes between discrete electronic levels offer the possibility of the protection of coherence and entanglement, as well as the determination of lifetime and environmental effect. These processes have been studied extensively via quantum dots. However, to push these observations to the atomic scale remains challenging. Using a scanning tunneling microscope at 15mK, we can study the tunneling between tip and sample Yu-Shiba-Rusinov (YSR) states, the sharp in-gap states generated by magnetic atoms on a superconductor. We call these new tunneling processes Shiba-Shiba tunneling, which is a realization of tunneling between single levels at the atomic scale. Shiba-Shiba tunneling indeed inherits features of tunneling between discrete levels, and the dependency of the transport on the normal state conductance provides a direct measurement of quasiparticle lifetime with atomic precision, which shows great potential as a general tool of measuring the lifetime of an impurity or topological levels such as Majorana bound states.