Scanning tunneling microscope observations of Si(111)3 × 1-Ag and 6 × 1-Ag structures

Using scanning tunneling microscopy, we have studied the Si(111)3 × 1-Ag and 6 × 1-Ag structures. The 3 × 1-Ag structure has been observed to consist of a bright row and two small protrusions. The bright row points in the directions, and the protrusions incline about 10° from the <11View the MathML source> directions, resulting to point in the diagonal directions of the 3 × 1 unit meshes. We found that the 6 × 1-Ag structure consists of alternative arrangements of two kinds of 3 × 1-Ag structures of which the protrusions incline about +10° and −10° from the <11View the MathML source> directions, respectively. Possible structural models for the 3 × 1-Ag and 6 × 1-Ag are proposed, based on the present STM results.