Scanning tunneling microscopy observation of Bi-induced surface structures on the Si(1 0 0) surface

Formation of new surface structures induced by bismuth adsorbates at the Si(1 0 0) surface has been investigated by scanning tunneling microscopy. Bismuth atoms that adsorbed on the surface at 500°C, form long linear belts in the Si(1 0 0) topmost layer. Each belt consists of two chains of bismuth dimers and substitutes for four Si-dimers per Si-dimer row in the terrace. At higher coverages of bismuth (∼3 ML) at 450°C, long linear structures with an arrangement of bismuth chains similar to the belt on the Si terraces are formed in the bismuth terraces. When bismuth was deposited on the clean Si(1 0 0) surface at room temperature and the surface was sequentially annealed, deep pits were constructed in bismuth-covered terraces. This result is attributed to the strain in the bismuth films.