The 6 x 6 and √39 x √39 phases of Ag/Ge(111) were studied by scanning tunnelling microscopy. Surface atomic structures of the 6 x 6 and the √39 x √39 phase were proposed in terms of additional Ag adatoms on top of a √3 x √3 layer described by the honeycomb-chain-trimer model. By varying the scanning tunnelling microscopy tip bias, the reconstruction could be changed reversibly between the √39 x √39 and the 6 x 6 phase. Besides the switching between two different phases, it was also possible to flip the domain orientation of the √39 x √39 phase. The mechanisms of the reconstruction transformation were discussed in terms of the role of the scanning tunnelling microscopy tip.

Scanning Tunnelling Microscopy Study of Ag/Ge(111) - Observation of Surface Reconstruction Transformations. H.M.Zhang, R.I.G.Uhrberg: Surface Science, 2003, 546[2-3], L789-96