Atomic structure model of the reconstructed Si(557) surface with a triple step structure: Adatom-parallel dimer model

Abstract

We studied the atomic and electronic structures of the reconstructed Si(557) surface composed of one (111) facet and three (112) facets in its single unit cell by using first principles calculations, scanning tunneling microscopy, and angle-resolved photoemission spectroscopy. A variety of atomic structure models of the (112) facet were introduced to understand overall properties of the Si(557) surface. Among the atomic structure models considered, an adatom-parallel dimer model with a missing dimer with the same bonding network as the $\text{Si}(111)\text{\ensuremath{-}}7\ifmmode\times\else\texttimes\fi{}7$ surface was found to be the most stable model. The scanning tunneling microscopy images and photoemission spectra of the Si(557) surface can be widely explained by the model. In addition, these results suggest that the (112) facet with a width of 0.9 nm can be used as a one-dimensional template, as the $\text{Si}(111)\text{\ensuremath{-}}7\ifmmode\times\else\texttimes\fi{}7$ surface plays the role of a two-dimensional template for various quantum dot arrays.