Inducing and Controlling Molecular Magnetism through Supramolecular Manipulation.

Diamagnetic H2 phthalocyanine molecules are probed on superconducting Pb(100) using a low-temperature scanning tunneling micoscope (STM). In supramolecular arrays made with the STM, the molecules acquire a spin as detected via the emergence of Yu-Shiba-Rusinov resonances. The spin moments vary among the molecules and are determined by the electrostatic field that results from polar bonds in the surrounding Pc molecules. The moments are further finely tuned by repositioning the hydrogen atoms of the inner macrocycle of the surrounding molecules.