Low-temperature photoemission study of the surface electronic structure ofSi(111)7×7

Abstract

The electronic structure of the $\mathrm{Si}(111)7\ifmmode\times\else\texttimes\fi{}7$ surface has been studied in detail at a sample temperature of 55 K with high-energy-resolution angle-resolved photoemission. The photoemission spectra show a previously undetected surface-state structure at \ensuremath{\approx}0.5 eV below the Fermi level that we assign to dangling-bond states located mainly to the adatoms near the corner holes of the $7\ifmmode\times\else\texttimes\fi{}7$ reconstruction. Detailed dispersion curves obtained at 55 K are presented for the three uppermost, dangling-bond derived, surface states. Surface sensitive Si $2p$ spectra obtained in this low-temperature study still show a comparatively broad line shape. Possible reasons for this are discussed.