Origin of the different formation modes of the oxygen added row overlayer on Ag(110) and Cu(110) surfaces

Abstract

Oxygen adsorption on Ag(110) and Cu(110) surfaces has been investigated by means of first-principles total-energy, and force calculations for repeated-slab geometries within the local density approximation (LDA). As for the chemisorption structure, the added row model speculated by the obserbed STM images is confirmed to be one of the stable structures, if bucking of the AgOAg added row and some distortions of the substrate structure are allowed. The adsorbed oxygen atom and noble metal atoms in the added row and in the surface first-layer are relaxed toward the configuration of the minimum total energy in terms of steepest descent method. Moreover comparing the optimized geometrics of the added row model of Ag(110)(n × 1)−O (n = 2, 3) and Cu(110)(2 × 1)−O, we obtain an important clue for the mechanism of the difference in the formation modes of the added row on Ag(110) and Cu(110) surfaces.