Two Ge-induced incommensurate phases, γ and β, were observed on Si(111) and were studied using in situ scanning tunnelling microscopy. The γ-phase consisted of aligned triangular domains whose stacking sequence was faulted with respect to the Si(111)-1x1 surface. The β-phase consisted of two kinds of triangular domain whose stacking sequences were faulted or unfaulted with respect to the Si(111)-1x1 surface. In the β-phase, two types of domain wall (zig-zag, face-to-face) formed in order to release the strain. The triangular domains all exhibited a quasi-1x1 hexagonal close-packed structure. By studying the evolution from magic clusters to incommensurate structures, structural models for the γ and β phases were proposed.

Atomic-Scale Study of Ge-Induced Incommensurate Phases on Si(111). R.Wu, L.L.Wang, Y.Zhang, X.C.Ma, J.F.Jia, Q.K.Xue: Chinese Physics Letters, 2010, 27[2], 026802