Long-range interaction of copper adatoms and copper dimers on Ag(111)

Abstract

Formation and motion of copper adatoms and addimers on Ag( 1 1 1) are investigated with low-temperature scanning tunnelling microscopy between 6 and 25 K. Adatoms move between fcc and hcp sites with a strong preference for the fcc site. Adatom motion and dimer rotation change due to the presence of other adatoms or dimers. Furthermore, rotating dimers influence other rotating dimers. These changes are attributed to changes in the diffusion or rotation potential, which are mediated by the electrons in the two-dimensional surface state band.