By using atomic-resolution scanning tunnelling microscopy and first-principles calculations, it was shown that Ge and Si(113) were structurally similar; contrary to previous conclusions. Both surfaces exhibited (3 x 2) and (3 x 1) reconstructions which were stabilized by surface self-interstitials, with (3 x 2) being lower in energy on Si but degenerate with (3 x 1) on Ge. Statistical analysis of the fluctuations which were observed between the 2 structures on Ge, combined with calculations for bulk interstitials, indicated that the surface (rather than the bulk) was the likely source and sink of surface self-interstitials for both materials.

Structure of Ge(113): origin and stability of surface self-interstitials A.Laracuente, S.C.Erwin, L.J.Whitman: Physical Review Letters, 1998, 81[23], 5177-80