Electronic structure and its dependence on local order for H/Si(111)-(1×1) surfaces

The valence and core level spectra of chemically prepared, ideally H-terminated Si(111) surfaces are characterized by remarkably sharp features. The valence band levels and their dispersion are well described by first-principles calculations using a quasiparticle self-energy approach within the GW approximation. From the ${\mathrm{Si}}_{2\mathit{p}}$ spectra, an upper limit of 35±10 meV is derived from the core hole lifetime broadening, a value substantially lower than previously measured.