Imaging the restatom of the Ge(111)-c(2 x 8) surface with noncontact atomic force microscopy at room temperature

The restatoms of the Ge(111)-c(2 x 8) surface are imaged by noncontact atomic force microscopy (NC-AFM) at room temperature. In the NC-AFM measurements on this surface, there are two types of topographic contrast images depending on the tip apex structure and/or composition. In one of them only the adatoms are imaged, while in the other both the adatom and the restatom are imaged. In some of the images in the latter case, the distinction between adatoms and restatoms is unclear due to a special configuration and/or composition of the tip apex. A small number of Sri atoms embedded in the surface allows the discrimination between the adatom and the restatom.