Metallic atomic wires on patterned dihydrogenated Si(001)

Electronic structure calculations are performed for atomic wires of metals like Al, Ga, and In placed on a patterned dihydrogenated $\mathrm{Si}(001):1\ifmmode\times\else\texttimes\fi{}1$ in search of structures with metallic behavior. The dihydrogenated Si(001) is patterned by depassivating hygrozen atoms only from one row of Si atoms along the $[1\overline{1}0]$ direction. Various structures of adsorbed metals and their electronic properties are examined. It is found that Al and Ga atomic wires with metallic property are strongly unstable towards the formation of buckled metal dimers leading to semiconducting behavior. Indium atomic wire, however, displays only marginal preference towards the formation of symmetric dimers staying close to the metallic limit. The reasons behind the lack of metallic atomic wires are explored. In addition, a direction is proposed for the realization of metallic wires on the dihydrogenated Si(001).