AB INITIO STUDY OF INDIUM QUANTUM WIRE FORMATION ON FLAT AND STEPPED Si(100) SURFACES

Using ab initio total energy calculations, we have studied the formation of indium (In) wires on flat and stepped Si(100)-(2×1) surfaces at low coverage. On flat Si(100), two possible orientations of In wires are examined: (i) the wire is perpendicular to the underlying Si dimer rows, and (ii) the wire is parallel to the underlying Si dimer rows. Total energy optimization shows that the energetically favored orientation is where the In wire is perpendicular to the underlying Si dimer rows, i.e. the wire is oriented along the [$1\bar{1}0$] direction. We have also considered two neighboring wires and determined the repulsive force between the two wires. On stepped Si(100) surfaces, the influence of SA and SB steps on In wire formation is investigated. The calculations suggest that In wires are likely to form at positions away from SA steps but close to SB steps.