An entire family of nano-scale trenches, ridges, and steps was observed experimentally on AsH3-exposed Si(100). Some of these line structures were observed previously, but their structures had remained a mystery. Theoretical modelling showed that they were all based upon the same stress-relieving 5-7-5 core structure. The strong similarities between line structures on As/Si(100), P/Si(100), As/Ge(100), and other V/IV surfaces lead to a much broader conclusion: 5-7-5 line structures were a general form of stress relief for group-V terminated Si and Ge surfaces.

5-7-5 Line Defects on As/Si(100) - a General Stress-Relief Mechanism for V/IV Surfaces. W.E.McMahon, I.G.Batyrev, T.Hannappel, J.M.Olson, S.B.Zhang: Physical Review B, 2006, 74[3], 033304 (4pp)