Molecular Kondo Lattice with Pure π-Magnetism on a Superconductor

Artificial Kondo lattices with tailored functionalities are the key to elucidating correlated quantum states. Here, we report a Kondo lattice based on organic π-magnetism in a perylene diimide monolayer on superconducting Pb(111). Using spectroscopic imaging scanning tunneling microscopy, we resolve Kondo resonances with uniform resonance widths that propagate across the entire molecular film, including both molecular cores and interstitial sites, demonstrating a periodic Kondo lattice with signatures consistent with lattice coherence. First-principles calculations unveil that the π-magnetism is induced via charge transfer from the substrate to an extended molecular orbital, with the intermolecular spin interaction mediated via hydrogen-bonding and conduction electrons. Furthermore, Yu-Shiba-Rusinov bands are generated in the molecular Kondo lattice, as induced by its interaction with the substrate superconductivity. Our work not only expands the Kondo lattice system to π-magnetism with s/p orbital character but also lays the foundation for tailoring the correlated states in view of the chemical versatility of molecules.