Scanning tunneling microscope study of bromine adsorbed on the Ag(111)surface

Bromine adsorbed silver (111) surfaces with (root 3 x root 3)R30 degrees an d (3 x 3) phases were studied by scanning tunneling microscopy at room temp erature. For the (root 3 x root 3)R30 degrees surface, no feature associate d with the Br overlayer could be obtained: only the substrate (1 x 1) struc ture was observed. On the other hand, for the (3 x 3) phase, it was reveale d that a bromine overlayer is formed with hexagonal arrangement, of which t he lattice constant is 3/2 that of the substrate. It was also found that th e coadsorbed cadmium atoms change the Br overlayer structure. (C) 1999 Else vier Science B.V. All rights reserved.