Trapping and moving atoms on surfaces

We have used a scanning tunneling microscope to laterally reposition a single cobalt atom adsorbed on the (111) face of a copper crystal. We find that the atom follows a complex path determined by the trapping potential of the STM tip, the effects of vibrational heating from inelastic electron scattering, and the overall potential landscape of the crystal surface. The atom's dynamical response produces the classic signature of a random two-state fluctuator, permits the acquisition of a binding site image of the surface, and suggests a methodology for atom-based measurements of nanostructures.