Angle-resolved photoemission measurements, combined with reflection high-energy electron diffraction, were made on As-stable, reconstructed (001)-(2 x 4) and c(4 x 4) GaAs surfaces prepared in situ by molecular beam epitaxy. A dangling-bond surface state having predominantly spz character was identified on the 2 x 4 surface, and a model for this structure based on dimerisation of adjacent surface As atoms proposed. The bridge bond between As atoms was tilted, and although largely of px character, had a pz component. The phasing of the dimer sequences was responsible for the orthogonal reconstruction. These conclusions were based on an atomic orbital approach, since band-structure calculations have not been performed for the reconstructed surface. Some similarity was observed, however, between the observed dispersion of a deeper lying back-bond state and that predicted from a calculation of the ideal 1 x 1 band structure by considering back-folding effects arising from reconstruction.

Angle-Resolved Photoemission from As-Stable GaAs (001) Surfaces Prepared by MBE. P.K.Larsen, J.H.Neave, B.A.Joyce: Journal of Physics C, 1981, 14[2], 167-92