Direct Electrical Access to the Spin Manifolds of Individual Lanthanide Atoms.

Lanthanide atoms show long magnetic lifetimes because of their strongly localized 4 electrons, but electrical control of their spins has been difficult because of their closed valence shell configurations. We achieved electron spin resonance of individual lanthanide atoms using a scanning tunneling microscope to probe the atoms bound to a protective insulating film. The atoms on this surface formed a singly charged cation state having an unpaired 6 electron, enabling tunnel current to access their 4 electrons. Europium spectra display a rich array of transitions among the 54 combined electron and nuclear spin states. In contrast, samarium's ground state is a Kramers doublet with a very large -factor of 5. These results demonstrate that all-electronic sensing and control of individual lanthanide spins is possible for quantum devices and spin-based electronics by using their rarely observed monovalent cation state.