The (100) surface was studied by means of atomic resolution scanning tunnelling microscopy. The use of cycles of low-energy ion bombardment and annealing resulted in the formation of an In-rich surface with a c(8 x 2) diffraction pattern. Filled-states images of the latter revealed a (4 x 1) periodicity which arose from the imaging of occupied lone-pair orbitals on exposed second-layer Sb atoms. Controlled deposition of Sb4 from a Knudsen effusion source, onto the c(8 x 2) surface at high temperatures, led to the formation of a(1 x 1), c(4 x 4) and asymmetrical (1 x 3) structures; in order of decreasing Sb/In ratio. Filled- and empty-states scanning tunnelling microscopic images of all of these Sb-rich reconstructions were generated, and coexistence of the various structures was also observed. The (1 x 1) and asymmetrical (1 x 3) surfaces exhibited a high degree of disorder, while the c(4 x 4) surface was highly ordered. The c(4 x 4) structure, which involved the chemisorption of Sb onto an already Sb-terminated surface, was characterized by blocks of 3 pairs of well-resolved Sb dimers.

C.F.McConville, T.S.Jones, F.M.Leibsle, S.M.Driver, T.C.Q.Noakes, M.O.Schweitzer, N.V.Richardson: Physical Review B, 1994, 50[20], 14965-76