New features of the Ge(111) surface with co-existing c(2 x 8) and 2 x 2 reconstructions investigated by scanning tunneling microscopy

The c(2x8) ground state reconstruction of the Ge(111) surface can be easily disrupted by the 2x2 reconstruction, since both of them are rather close to each other in terms of the surface free energy. Both structures are comprehensively studied in the literature. However, new surface features can be found on the borders between c(2x8) and 2x2 domains of various registries and orientations. We report scanning tunneling microscopy observations and suggest atomic models for the linear chains of 2x2 cells or c(2x4) cells, as well as adatom/restatom group vacancies, including corner holes of a similar geometry, like the case of the Si(111)-7x7 surface