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arXiv · 2304.13697

Proximity-induced superconductivity in a 2D Kondo lattice of an f-electron-based surface alloy

Howon Kim·Dirk K. Morr·Roland Wiesendanger
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Abstract

Realizing hybrids of low-dimensional Kondo lattices and superconducting substrates leads to fascinating platforms for studying the exciting physics of strongly correlated electron systems with induced superconducting pairing. Here, we report a scanning tunneling microscopy and spectroscopy study of a new type of two-dimensional (2D) La-Ce alloy grown epitaxially on a superconducting Re(0001) substrate. We observe the characteristic spectroscopic signature of a hybridization gap evidencing the coherent spin screening in the 2D Kondo lattice realized by the ultrathin La-Ce alloy film on normal conducting Re(0001). Upon lowering the temperature below the critical temperature of rhenium, a superconducting gap is induced with an in-gap Shiba band arising from the interaction of residual unscreened magnetic moments with the superconducting substrate. A positive correlation between the Kondo hybridization gap and the binding energy of the subgap Shiba band maximum is found. Our results open up a promising route toward the design of artificial superconducting Kondo and heavy fermion systems.

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Howon Kim, Dirk K. Morr, Roland Wiesendanger. 2023-04-26. Proximity-induced superconductivity in a 2D Kondo lattice of an f-electron-based surface alloy. https://arxiv.org/abs/2304.13697

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