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arXiv · 2112.11804

Structural and Superconducting Properties of Ultrathin Ir Films on Nb(110)

Philip Beck·Lucas Schneider·Lydia Bachmann·Jens Wiebe·Roland Wiesendanger
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Abstract

The ongoing quest for unambiguous signatures of topological superconductivity and Majorana modes in magnet-superconductor hybrid systems creates a high demand for suitable superconducting substrates. Materials that incorporate $s$-wave superconductivity with a wide energy gap, large spin-orbit coupling, and high surface quality, which enable the atom-by-atom construction of magnetic nanostructures using the tip of a scanning tunneling microscope, are particularly desired. Since single materials rarely fulfill all these requirements we propose and demonstrate the growth of thin films of a high-Z metal, Ir, on a surface of the elemental superconductor with the largest energy gap, Nb. We find a strained Ir(110)/Nb(110)-oriented superlattice for one to two atomic layer thin films, which transitions to a compressed Ir(111) surface for 10 atomic layer thick films. Using tunneling spectroscopy we observe proximity-induced superconductivity in the latter Ir(111) film with a hard gap $\Delta$ that is $85.3\%$ of that of bare Nb(110).

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Philip Beck, Lucas Schneider, Lydia Bachmann, Jens Wiebe, Roland Wiesendanger. 2021-12-22. Structural and Superconducting Properties of Ultrathin Ir Films on Nb(110). https://arxiv.org/abs/2112.11804

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