Two-dimensional quantum diffusion of Gd adatoms in nano-size Fe corrals.

Gd atom diffusion in 30-nm-diameter Fe quantum corrals is studied utilizing scanning tunneling microscopy and kinetic Monte Carlo (KMC) simulations. The Gd adatom probability distribution inside the corral forms several trajectories and is closely related to oscillations of the local density of states at the Fermi level, as revealed by spectroscopy measurements. With increasing coverage, the Gd adatoms form a ringlike structure within the vicinity of the quantum corrals. The results are explained with KMC calculations utilizing experimentally determined long-range interactions and quantum confinement. The findings demonstrate that the diffusion of Gd adatoms is significantly influenced by the quantum corrals and that novel quantum ring structures can be created via control of the coverage. [ABSTRACT FROM AUTHOR]