Magnetic Ground State Discrimination of a Polyradical Nanographene Using Nickelocene-Functionalized Tips

Molecular magnets are a promising class of materials with exciting properties and applications. However, a profound understanding and application of such materials depend on the accurate detection of their electronic and magnetic properties. Despite the availability of experimental techniques that can sense the magnetic signal, the exact determination of the spin ground states and spatial distribution of the exchange interaction of strongly correlated single-molecule magnets remain challenging. Here, we demonstrate that scanning probe microscopy with a nickelocene-functionalized probe can distinguish between nearly degenerate multireference ground states of single-molecule π-magnets and map their spatial distribution of the exchange interaction. This method expands the already outstanding imaging capabilities of scanning probe microscopy for characterizing the chemical and electronic structures of individual molecules, paving the way for the study of strongly correlated molecular magnets with unprecedented spatial resolution.