Moiré superlattice of a charge transfer Kondo monolayer and its interplay with superconductivity

Moiré pattern formation has emerged as a powerful tool to create controllable two-dimensional electronic superlattices. Moiré superlattices can exhibit remarkable properties such as unconventional superconductivity and Mott insulators in twisted graphene bilayers, and moiré exciton bands in transition metal dichalcogenide heterobilayers. Here, we report on the observation of a moiré superlattice formed between an organic monolayer and a s-wave superconductor. Although the organic molecule does not contain magnetic atoms, the interlayer charge transfer from the superconductor to the p-orbitals creates a local moment leading to the co-existence of Kondo screening and Cooper pair formation, and to an interplay between superconductivity and the Kondo effect. More specifically, the moiré pattern leads to a strong modulation of the “local” Kondo temperature by a factor of three. In addition, the interplay of Kondo screening and Cooper pair formation leads to a modulation of the pairing gap by about 30%. We show that the periodicity of these superlattices is tunable by the twist angle, making it possible to tailor the properties of this heterostructure.