Electronic and magnetic properties of lanthanide atomic chains and nanostructures assembled atom-by-atom

The electrons hosted by metallic chains of atoms constitute one of the simplest cases of analytically solvable electronic structure: a quantum particle in a 1-dimensional box. Such states have previously been realized by constructing chains of individual metal atoms by using the tip of a scanning tunneling microscope, but it has thus far been challenging to create long chains, branched structures, and related nanostructures in a way that they are electrically insulated from the underling substrate. We construct low-dimensional nanostructures hosting delocalized electrons by arranging individual samarium and europium atoms on an epitaxial thin film of magnesium oxide. Use of tunneling spectroscopy and electron spin resonance reveals a rich set of electronic and magnetic properties that arise from the low-dimensional confinement. Further properties arises from the coupling of the delocalized electrons to the highly localized magnetic moments of the lanthanide 4f electrons. These results provide new opportunities to study novel electronic and magnetic phenomena at the intersection of low-dimensional confinement, strong spin-orbit coupling, and large localized magnetic moments.