Phys.org December 21, 2022
Complexes containing rare-earth ions attract great attention for their technological applications ranging from spintronic devices to quantum information science. While charged rare-earth coordination complexes are ubiquitous in solution, they are challenging to form on materials surfaces that would allow investigations for potential solid-state applications. A team or researchers in the US (Argonne National Laboratory, Ohio University, University of Illinois) has demonstrated formation and atomically precise manipulation of rare-earth complexes on gold surface. Although they are composed of multiple units held together by electrostatic interactions, the entire complex rotates as a single unit when electrical energy is supplied from a scanning tunneling microscope tip. Despite the hexagonal symmetry of the gold surface, a counterion at the side of the complex guides precise three-fold rotations and 100% control of their rotational directions was achieved using a negative electric field from the scanning probe tip. This work demonstrates that counterions can be used to control dynamics of rare-earth complexes. The key ingredient is a single atom of europium, a rare earth element. It rests at the center of a complex of different atoms and gives the molecule many potential applications, such as, next generation microelectronics, quantum technologies, catalysis to speed up reactions, conversion of light into electricity and more…read more. Open Access TECHNICAL ARTICLE
…Europium complex before and after rotation by 120 degrees (b,c). Dashed circle indicates negatively charged molecule. Credit: Argonne National Laboratory.