Antiferromagnetism-driven two-dimensional topological nodal-point superconductivity
[ 1 ] Instytut Fizyki, Wydział Inżynierii Materiałowej i Fizyki Technicznej, Politechnika Poznańska | [ P ] employee
2023
scientific article
english
- magnetic properties and materials
- superconducting properties and materials
- surfaces
- interfaces and thin films
- topological matter
EN 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. Here 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.
04.02.2023
614-1 - 614-7
Article number: 614
CC BY (attribution alone)
open journal
final published version
at the time of publication
200
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