Imaging of the electronic states on the Si(111)1 x 1-As surface using a display-type photoelectron analyzer

We have measured the electronic structure of the arsenic-terminated Si(111) 1 x 1-As surface with angle-resolved photoemission using a display-type ana lyzer. The analyzer records energy-resolved angular distribution patterns o f the photoelectrons in a solid angle of Delta theta = 43 degrees and Delta phi = 360 degrees, thereby covering the entire surface Brillouin zone at t he binding energies measured here. Using this instrument we have mapped the entire two-dimensional dispersion of the lone-pair surface state, from the band maximum at <(<Gamma>)over bar> to the global minima at the (K) over b ar -points. In addition, the two-dimensional dispersions of the three upper valence bands are mapped. showing their threefold symmetry, using a photon energy of 21.2 eV. Our results are in good agreement with previous experim ents and earlier quasiparticle band structure calculations. (C) 2001 Elsevi er Science B.V. All rights reserved.