SKM 2021 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Focus Session: Emerging Phenomena in Superconducting Low Dimensional Hybrid Systems I

TT 6.5: Vortrag

Dienstag, 28. September 2021, 11:45–12:15, H7

Majorana bound states in magnetic impurity chains on conventional superconductors — •Annica Black-Schaffer — Uppsala University, Uppsala, Sweden

Magnetic impurities on the surface of spin-orbit coupled but otherwise conventional superconductors offer the possibility to create topological phases with Majorana bound states (MBSs) without having to apply an external magnetic field. In this talk I will present some of our resent results in modeling both magnetic impurity wires and islands on the surface of spin-orbit coupled superconductors, including a self-consistent treatment of the superconductivity, which results in a local π-shift of superconducting order parameter near magnetic impurities. In particular, I will show how MBSs at wire end points very strongly hybridize with in-gap Yu-Shiba-Rusinov (YSR) states, causing large oscillations in the MBSs energies that are significantly enhanced within the self-consistent treatment. Still, by treating the MBSs as topological boundary modes dependent only on the effective mass gap, we can arrive at a fully parameter-free fitting of the Majorana localization length, which stays very short. I will also show how the wire end point MBSs are very robust against disorder within a self-consistent treatment, despite individual YSR states being extremely sensitive to disorder. Finally, despite the importance of a self-consistent treatment of superconductivity for the properties of the MBSs, I will show how the π-shift cannot easily be measured using the Josephson effect.