'Atom-interchange Manipulation' using Non-contact Atomic Force Microscopy

We demonstrate a novel atom manipulation method of ‘Atom-interchange manipulation’ using non-contact atomic force microscopy (NC-AFM). Previously, methods of lateral atom manipulation are performed by manipulating single atoms or molecules adsorbed on metallic surfaces, but in this paper the atom-interchange manipulation is performed by interchanging two different atom species embedded in semiconductor surface layers. We use a Sn/Ge(111)-c(2×8) surface for the Atom-interchange manipulation, where some Ge adatoms are substituted by Sn adatoms. Although the diffusion rate of Sn adatoms is very low at room temperature, the atom interchange between selected Sn adatom and Ge adatom can be controlled by the NC-AFM tip. ‘Atom inlay’, that is, artificial atomic patterns formed from embedded Sn atoms in the plane of the Ge surface, is created at room temperature by rearranging configuration of two kind of atom species on the surface. This paper describes our first experiment of the atom assembly using AFM.