INSB(211) STUDIED BY PHOTOELECTRON-SPECTROSCOPY AND SCANNING-TUNNELING-MICROSCOPY

The two inequivalent sides of InSb(211) have been studied by scanning tunneling microscopy (STM), angle-resolved photoelectron spectroscopy (ARPS) and low-energy electron diffraction (LEED). Despite identical s puttering-annealing preparations, the surface qualities are very diffe rent in the two cases. The (211)A surface has a high degree of disorde r reflected by a poor (1 x 1) LEED pattern and a lack of well-defined surface-induced Features in valence band ARPS. In STM, this surface sh ows small (211) terraces with a high density of steps. The In core lev el spectrum of (211)A suggests presence of a metallic component. In co ntrast, the (211)B surface is ordered, with large flat terraces, and s hows a sharp (1 x 1) LEED pattern. The In and Sb core level spectra ar e well fitted with one surface shifted component and show no sign of m etallic In. In the valence band spectra, three surface-induced bands a re observed. A tentative explanation for the asymmetry between the A- and B-sides in terms of bonds on the ideal surface is proposed. (C) 19 98 Published by Elsevier Science B.V.