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

Bromine adsorbed silver (111) surfaces with (√3 × √3)R30° and (3 × 3) phases were studied by scanning tunneling microscopy at room temperature. For the (√3 × √3)R30° surface, no feature associated with the Br overlayer could be obtained; only the substrate (1 × 1) structure was observed. On the other hand, for the (3 × 3) phase, it was revealed that a bromine overlayer is formed with hexagonal arrangement, of which the lattice constant is 3/2 that of the substrate. It was also found that the coadsorbed cadmium atoms change the Br overlayer structure.