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TT: Fachverband Tiefe Temperaturen
TT 32: Superconductivity: Yu-Shiba-Rusinov and Andreev Physics
TT 32.3: Talk
Wednesday, March 19, 2025, 15:30–15:45, H32
Spin Dynamics in a Josephson Junction Between Two Superconducting Magnetic Impurity States — Fabian Ziesel1, Björn Kubala1,2, Joachim Ankerhold1, and •Ciprian Padurariu1 — 1ICQ and IQST, Ulm University, Germany — 2Institute of Quantum Technologies, German Aerospace Center (DLR), Ulm, Germany
We study the Josephson effect in a junction formed between two superconducting magnetic impurities. Such a junction was recently realized using a scanning tunneling microscope tip functionalized with a magnetic impurity that probes a second impurity on the sample [1]. Our work extends a recent theoretical investigation [2] by considering the mutually coupled dynamics between the impurity spins and the Josephson phase. We suggest that the Josephson effect can be exploited to manipulate the relative magnetic orientation of the impurities due to a Josephson-induced exchange interaction that arises.
Our theoretical approach treats the Josephson and spin dynamics equally. We identify a key experimental signature of spin dynamics: a small d.c. bias results in excess d.c. current due to the coupling between spins and the Josephson phase. We also discuss spin control, exemplified by inducing a spin-flip of an impurity using an adiabatic voltage pulse.
[1] H. Huang et al., Phys. Rev. Res. 3, L032008 (2021);
[2] S. Chakraborty et al., Phys. Rev. B 108, 094518 (2023).
Keywords: Yu-Shiba-Rusinov states; Josephson effect; spin dynamics; spin torque; superconducting junction