Electronic structure of Au-induced surface phases on Si(110): LEED and angle-resolved photoemission measurements

Abstract

Au-induced reconstructions of the Si(110) surface have been studied using low-energy electron diffraction and angle-resolved photoemission (ARP). Low-energy electron diffraction reveals three well-ordered phases: $1\ifmmode\times\else\texttimes\fi{}2$, $2\ifmmode\times\else\texttimes\fi{}5$, and $(4,0)\ifmmode\times\else\texttimes\fi{}(\overline{1},3)$, depending on the Au coverage in accordance with previous studies. The highest coverage phase is observed to be mixed with a $(4,0)\ifmmode\times\else\texttimes\fi{}(\overline{3},3)$ phase. ARP spectra show no clear surface-state bands on the $1\ifmmode\times\else\texttimes\fi{}2$ surface within the bulk band gap. The $2\ifmmode\times\else\texttimes\fi{}5$ surface composed of one-dimensional (1D) atomic chain exhibits two dispersive metallic bands with exact quarter and half fillings. Their Fermi surfaces are straight lines within the experimental accuracy indicating strong 1D characters. This phase is thus one of the most ideal 1D metallic systems ever fabricated on solid surfaces. The $(4,0)\ifmmode\times\else\texttimes\fi{}(\overline{1},3)$ surface has only one strongly dispersing but semiconducting band following the $\ifmmode\times\else\texttimes\fi{}2$ periodicity apparently.