Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 30: Surface Magnetism
O 30.1: Vortrag
Dienstag, 18. März 2025, 10:30–10:45, H11
Spin-polarized chiral edge modes in the topological nodal-point superconductor Mn/Ta(110) — •Felix Zahner1, Felix Nickel2, Roberto Lo Conte3, Tim Drevelow2, Roland Wiesendanger1, Stefan Heinze2, and Kirsten von Bergmann1 — 1University of Hamburg, Germany — 2University of Kiel, Germany — 3University of Groningen, The Netherlands
Topological superconducting phases in magnet-superconductor hybrid (MSH) - systems have been investigated recently due to their potential applications in quantum devices. Zero-energy states and chiral edge modes have previously been observed in ferromagnetic 1D [1] and 2D [2] MSH systems. In a 2D antiferromagnet (AFM) MSH and a spin spiral MSH system, gapless topological nodal-point superconducting (TNPSC) phases have been observed [3, 4].
Using scanning tunnelling microscopy/spectroscopy (STM/S), we investigate the mono- and bilayers on a Ta(110) surface. Both exhibit local AFM order and tight-binding calculations indicate that both host a TNPSC phase. Interestingly, we observe edge modes not only at the boundaries between the TNPSC and the topologically trivial superconducting substrate, but also at specific boundaries between these two AFM systems of Mn mono- and bilayer. Our spin-polarized STM measurements reveal a significant spin-polarization of this edge mode, which we discuss based on the tight-binding results.
[1] Nadj-Perge, S. et al., Science 346, 602 (2014). [2] Palacio-Morales, A. et al., Sci. Adv. 5, eaav6600 (2019). [3] Bazarnik, M. et al, Nat Commun 14, 614 (2023). [4] Brüning, R. et al., arXiv:2405.14673.
Keywords: Superconductivity; Scanning tunneling microscopy; Antiferromagnetism; Topology