Atomic resolution scanning tunnelling microscopic images of ordered (110) surfaces in aqueous 0.1M HClO4 were studied as a function of the electrode potential. It was found that lowering the potential of a freshly annealed surface to -0.3VSCE yielded images which consisted mainly of domains with 1 x 2 symmetry. Although the 1 x 2 structure exhibited an atomic density that was commensurate with the usual missing-row model, the images suggested that significant relaxation of the top- and second-layer atoms occurred. Three-atom wide ribbons, lying along the [1¯10] direction, were seen to provide the basic building blocks for reconstruction. These units also yielded added-row domains of (1 x n) symmetry, where n was equal to, or greater than, 3. The (110) reconstruction became 1 x 1, within 2s, upon changing the potential to 0VSCE. It reappeared immediately upon changing back to -0.3V.

X.Gao, A.Hamelin, M.J.Weaver: Physical Review B, 1991, 44[19], 10983-6