Ab initio calculations of the optical properties of the Si(113) 3X2 adatom-dimer-interstitial surface

We investigated the stable silicon (113) surface with a 3x2 adatom-dimer-interstitial reconstruction by ab initio methods. The ground-state properties have been obtained using density-functional theory. We present the dispersion of the electronic band structure, where the surface bands have been distinguished from the projected bulk bands by calculating their localization in the slab. The optical spectra, here the reflectance anisotropy spectra (RAS), have been obtained within the independent-particle random-phase approximation. We identified surface features in the spectra, tracing them back to the responsible electronic states, and studied their localization in the slab. Theoretical results for the band structure and the RAS are compared with available experimental data.