“…Si(111) and its vicinal surfaces, in particular, have shown a variety of chain structures after depositing a submonolayer of metal atoms. Indium [1] and Au ( [2,3] and references therein) form quasi-one-dimensional (1D) metallic chains but semiconducting structures can also be formed. One of the best known of these latter metalinduced reconstructions is the Si(111)-(3 × 1)-X structure, which is formed by various adsorbates, X, such as alkali metals (Li, Na, K), alkaline-earth metals (Mg, Ca, Ba), rare-earth metals (Sm, Yb), and Ag, at a coverage of 1/3 monolayer (ML).…”