High-resolution photoemission spectroscopy study of the single-domainSi(110)−16×2surface

Abstract

We have investigated the valence band structure and $\mathrm{Si}\phantom{\rule{0.3em}{0ex}}2p$ photoemission spectra of the single-domain $\mathrm{Si}(110)\text{\ensuremath{-}}16\ifmmode\times\else\texttimes\fi{}2$ surface with higher resolution than previous studies. We found that the highest occupied surface state, reported to be dispersive in the previous studies, is resolved into the two surface states with flat energy dispersions. This reveals that the two surface states are not produced by Si $\ensuremath{\pi}$-bonded chains, as suggested in the previous studies, but originate from the building blocks with spatially localized electronic structures such as a Si tetramer and a Si adatom. $\mathrm{Si}\phantom{\rule{0.3em}{0ex}}2p$ line shapes show directly five surface components without any curve fitting. Various atomic structure models, especially the adatom-tetramer-interstitial model, of the $\mathrm{Si}(110)\text{\ensuremath{-}}16\ifmmode\times\else\texttimes\fi{}2$ surface are considered to figure out the atomistic origins of the surface components and states.