The atomic structure of the c(8 x 2) reconstruction of (001) surfaces, as determined using surface X-ray diffraction, was determined. It was found that group-III dimers were not prominent on the surface, and the sub-surface dimerization of group-III atoms instead took place in the second bilayer. This was accompanied by a major rearrangement of the surface atoms, above the dimers, to form linear arrays. By varying the occupancies of 4 surface sites, the (001)-c(8 x 2) reconstructions of III-V semiconductors could be described by a unified model.

Sub-Surface Dimerization in III-V Semiconductor (001) Surfaces. C.Kumpf, L.D.Marks, D.Ellis, D.Smilgies, E.Landemark, M.Nielsen, R.Feidenhans, J.Zegenhagen, O.Bunk, J.H.Zeysing, Y.Su, R.L.Johnson: Physical Review Letters, 2001, 86[16], 3586-9