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O: Fachverband Oberflächenphysik
O 7: Spins on Surfaces at the Atomic Scale I
O 7.5: Talk
Monday, March 27, 2023, 11:45–12:00, REC C 213
Magnetic impurity states proposed as thermometer for superconducting quasiparticle temperatures — •Ciprian Padurariu1, Sujoy Karan2, Haonan Huang2, Björn Kubala1,3, Christian R. Ast2, and Joachim Ankerhold1 — 1Institute for Complex Quantum Systems and IQST, Ulm University, Ulm, Germany — 2Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany — 3Institute of Quantum Technologies, German Aerospace Center (DLR), Ulm, Germany
The occupation of the quasiparticle continuum in a superconductor is of critical importance for the functionality of Josephson junction-based quantum devices. While significant progress has been made recently, the detection and trapping of quasiparticles remains a significant challenge. This talk will describe the design of a thermometer that detects the presence and effective temperature of superconducting quasiparticles. The device consists of a mK-STM functionalized with a single Yu-Shiba-Rusinov (YSR) state inside the gap. Transport between the tip and a clean superconducting substrate shows Zeeman-split peaks in the differential conductance associated to the YSR state [1]. The current is sensitive to quasiparticles above the gap. We show, based on a simple rate equation model, how the control of the magnetic field, as well as the voltage bias, allows the operation of the junction as a thermometer for the effective temperature of quasiparticles.
[1] W.-V. van Gerven Oei, et al., "Magnetic impurities in spin-split superconductors", Phys. Rev. B 95, 085115 (2017).