Atomic structures of kinks at double-layer steps on Si(100) surfaces

We studied the kink structures at double-layer step by scanning tunneling m icroscopy and catalogued the kinks into two types: complex kinks (composed of minus kinks and plus kinks) and simple kinks (only minus or plus kinks). Both of the kinks create a local A terrace. The dimers in the local A terr ace are bucked. For a complex kink, the buckling of the dimers in the local A terrace is determined by the interaction of the buckled dimers propagate d from minus kinks and plus kinks. For a simple kink, the buckling of the d imers in the local A terrace is determined by the buckling of the rebonded dimers at step edges. The directions of the buckled dimers are determined b y the tensile stress between dimer rows. The brightness of the outermost di mers in an upper terrace is caused by the buckling of the dimers and the ch arge transfer between the two atoms of the dimers. (C) 2000 Elsevier Scienc e B.V. All rights reserved.