Tailored Spin Coupling of Single-Molecule Magnets with a Single Charge-Density-Wave Metal Layer

The interplay between spin and charge can give rise to remarkable quantum states of matter. A celebrated example is the Kondo effect, which occurs when localized magnetic impurities are screened by itinerant electrons. While significant advances have been made in probing the Kondo effect in systems consisting of magnetic impurities adsorbed on conventional bulk metals, its manifestation on unconventional metals with strong many-body interactions, particularly down to atomic-layer thickness, has hitherto remained unexplored. Here we investigate the charge and spin interaction between magnetic cobalt phthalocyanine (CoPc) molecules acting as spin-bearing Kondo impurities and a single, substrate supported layer of the charge-density-wave (CDW) metal H-NbSe₂. Remarkably, we present unambiguous Kondo signatures on certain adsorption sites. We identify four distinct configurations depending on the position of the Co²⁺ ion relative to the atomic lattice and the CDW superlattice of NbSe₂. We show precise control of the Kondo effect by reversible repositioning of the CoPc molecule between the different positions. Our scanning tunneling microscopy (STM) and spectroscopy (STS) measurements further reveal the symmetry breaking of the Kondo resonance, indicating a pronounced magnetic anisotropy in CoPc/NbSe₂. More importantly, this interaction can induce local magnetism into the nonmagnetic NbSe₂ layer, offering new possibilities for tailoring spin textures.