SPUTTERED AND ANNEALED INAS(111)OVER-BAR - AN UNRECONSTRUCTED SURFACE

The electronic structure of the InAs(111BAR)1 X 1 surface has been inv estigated by angle resolved photoelectron spectroscopy along the symme try lines GAMMAKBAR, GAMMAMBAR, and GAMMAMBAR of the surface Brillouin zone. The bulk valence band structure was calculated using a combinat ion of the linear augmented plane-wave method and the relativistic aug mented plane-wave method. We have projected the theoretical bulk band structure onto the surface Brillouin zone to separate surface states f rom surface resonances. Two surface related structures, S1 and S2, hav e been observed and their E(i)(k(parallel-to)) dispersions are establi shed. Both S1 and S2 show the symmetry of the 1 X 1 surface Brillouin zone, which is consistent with the observed 1 X 1 LEED pattern. We ide ntify S1 as the As-derived dangling bond state, and S2 is associated w ith the backbonds connecting the As atoms in the surface layer with th e underlying In layer.