SKM 2021 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Transport (joint session TT/DY)
TT 28.1: Vortrag
Freitag, 1. Oktober 2021, 13:30–13:45, H6
Spin-relaxation in superconducting graphene systems — •Michael Barth, Jacob Fuchs, Andreas Costa, Klaus Richter, Jaroslav Fabian, and Denis Kochan — Universität Regensburg
The spin-relaxation time τs is a fundamental quantity as it determines how long spins can propagate before they relax. For quasi-particles in s-wave superconductors that scatter off magnetic impurities this quantity is expected to decrease by lowering the temperature, known as the Hebel-Slichter-effect [1]. We have shown that this decrease of the spin-relaxation time does not happen generally in all superconductors [2]. A completely opposite behavior can be observed, if Yu-Shiba-Rusinov (YSR) states develop deeply inside the superconducting gap, since then the magnetic moments energetically decouple from the coherence peaks what in turn weakens an exchange interaction with quasi-particles. By employing analytical and numerical methods we have shown that such deep lying in-gap YSR states are formed if a system with magnetic impurities is doped to resonances. As an explicit example we will present results for graphene and bilayer graphene decorated with light magnetic impurities as hydrogen and fluorine.
[1] L. C. Hebel and C. P. Slichter, Phys. Rev. 113, 1504 (1959)
[2] D. Kochan, M. Barth, A. Costa, K. Richter, J. Fabian, Phys. Rev. Lett. 125, 087001 (2020)