Structural analogy between GeSi(111)-5x5 and Si(111)-7x7 surfaces.

Low energy electron diffraction (LEED) patterns for GeSi(111)- 5x5 surface are reported and compared to those for Si(111)- 7x7 surface. Parallels between the observed LEED patterns are explained by a structural analogy between GeSi(111)-5x5 and Si(111)-7x7 surfaces. Both the (5x5) and (7x7) patterns are shown to be consistent with structural models of the triangle- dimer type previously proposed for Si(111)-7x7 surface.