Regensburg 2022 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 30: Surface Magnetism
MA 30.2: Vortrag
Donnerstag, 8. September 2022, 09:45–10:00, H48
Low-energy end states in proximitized antiferromagnetic nanowires — Lucas Schneider1, Philip Beck1, Thore Posske2,3, Levente Rózsa4, •Jens Wiebe1, and Roland Wiesendanger1 — 1Department of Physics, Universität Hamburg, D-20355 Hamburg, Germany — 2I. Institute for Theoretical Physics, Universität Hamburg, D-20355 Hamburg, Germany — 3The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany — 4Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
Magnetically ordered nanowires coupled to a superconducting surface have been proposed to host Majorana modes (MMs) at their ends, which form a single, highly non-local fermionic state together. While multiple experiments claim the observation of MMs via a zero-bias resonance in tunneling conductance at the ends of nanowires, this is not a unique signature of MMs. In this work, we study the emergence of low-energy end states in artificially crafted antiferromagnetic nanowires on two different superconducting surfaces using scanning tunneling spectroscopy. While some of the end states are observed close to zero energy, we find that they can be split into two non-degenerate components localized on the left and right ends by local defects - in clear contrast to expectations for a single non-local state. The phenomenology of these trivial bound states can be explained by simple toy-model calculations. We propose that similar perturbations by local defects could be used on other sample systems to probe the stability of candidate topological edge modes against local disorder.