Atomic structure and formation kinetics of the Sb/Si(111)-53×53surface

We report on the observation of the 5$\sqrt{3}$×5$\sqrt{3}$ atomic structure of an Sb-passivated Si(111) surface using low-energy electron diffraction and scanning tunneling microscopy (STM). A model of this structure has been derived from the analysis of high-resolution STM images. The stability of the Sb/Si(111)-5$\sqrt{3}$×5$\sqrt{3}$ structure has been found to come from the saturation of dangling bonds and the site-selective replacement of Si atoms with Sb atoms. Strain induced by stacking faults and lattice mismatch is found to be responsible for the site selectivity in the replacement. The kinetics of formation is also discussed.