Maciej Bazarnik^1,2*, Roberto Lo Conte^1*, Eric Mascot^1,3*, Kirsten von Bergmann¹, Dirk K. Morr⁴, Roland Wiesendanger¹

1 Department of Physics, University of Hamburg, D-20355 Hamburg, Germany

2 Institute of Physics, Poznan University of Technology, Piotrowo 3, 60-965 Poznan, Poland

3 School of Physics, University of Melbourne, Parkville, VIC 3010, Australia

4 Department of Physics, University of Illinois at Chicago, Chicago, IL 60607

* Corresponding authors emails: mbazarni@physnet.uni-hamburg.de, rolocont@physnet.uni-hamburg.de, eric.mascot@unimelb.edu.au

DOI10.24435/materialscloud:41-ff [version v1]

Publication date: Dec 13, 2022

How to cite this record

Maciej Bazarnik, Roberto Lo Conte, Eric Mascot, Kirsten von Bergmann, Dirk K. Morr, Roland Wiesendanger, Antiferromagnetism-driven two-dimensional topological nodal-point superconductivity, Materials Cloud Archive 2022.173 (2022), doi: 10.24435/materialscloud:41-ff.

Description

Magnet/superconductor hybrids (MSHs) hold the promise to host emergent topological superconducting phases. Both one-dimensional (1D) and two-dimensional (2D) magnetic systems in proximity to s-wave superconductors have shown evidence of gapped topological superconductivity with zero-energy end states and chiral edge modes. Recently, it was proposed that the bulk transition-metal dichalcogenide 4Hb-TaS2 is a gapless topological nodal-point superconductor (TNPSC). However, there has been no experimental realization of a TNPSC in a MSH system yet. In our work we present the discovery of TNPSC in antiferromagnetic (AFM) monolayers on top of an s-wave superconductor. Our calculations show that the topological phase is driven by the AFM order, resulting in the emergence of a gapless time-reversal invariant topological superconducting state. Using low-temperature scanning tunneling microscopy we observe a low-energy edge mode, which separates the topological phase from the trivial one, at the boundaries of antiferromagnetic islands. As predicted by the calculations, we find that the relative spectral weight of the edge mode depends on the edge’s atomic configuration. Our results establish the combination of antiferromagnetism and superconductivity as a novel route to design 2D topological quantum phases. This record contains tight binding calculations results and a combination of STM images and tunneling spectroscopy data supporting our work.

Materials Cloud sections using this data

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README.txt MD5md5:c42943ae4e2f3faff0dea147d9a994b0	580 Bytes	Describes the contents of the record, the file formats, and ways to open the data.

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Keywords

scaning tunneling microscopy nodal point superconductivity topological quantum materials