Exchange-induced suppression of superconductivity in a nano-skyrmion lattice - superconductor hybrid

Engineered magnet-superconductor hybrids have recently been identified as promising platforms for the investigation of topological superconductivity. Beyond ferro- and antiferromagnetic structures, coupling non-collinear spin textures, such as skyrmion lattices, to superconductors offers an exciting route for creating and manipulating unconventional superconducting states. In this work, by preparing monolayer Fe on Ir(111) thin films grown epitaxially on a Nb(110) surface, we realize a hybrid system of a nano-skyrmion lattice proximitized to a superconducting substrate. Scanning tunneling spectroscopy shows that superconductivity becomes suppressed by the Fe nano-skyrmion lattice, with both the superconducting gap and coherence peaks disappearing. Tight-binding calculations reveal that with increasing exchange coupling, the gap is progressively filled up and eventually superconductivity gets quenched. These results reveal microscopic constraints for designing topologically non-trivial states based on magnet-superconducting heterostructures.