Triangular-tiled arrangement of7×7and ‘1×1’ domains on Si(111)

Abstract

Ultrahigh-vacuum scanning electron microscopy reveals the presence of an ordered domain pattern with threefold symmetry on Si(111). During the transition between $7\ifmmode\times\else\texttimes\fi{}7$ and `$1\ifmmode\times\else\texttimes\fi{}1$' phases on a Si(111) surface misoriented to 〈112\ifmmode\bar\else\textasciimacron\fi{}〉, triangular $7\ifmmode\times\else\texttimes\fi{}7$ domains nucleate at the upper edge of the step, and grow into the terrace. When the apex of the domain reaches the lower edge, the $7\ifmmode\times\else\texttimes\fi{}7$ and `$1\ifmmode\times\else\texttimes\fi{}1$' domains form a triangular-tiled arrangement. This triangular-tiled arrangement is explained in terms of elastic-stress relaxation effects.