Evolution from Alloying to Nanostrips of Sb on Ag(110) Probed by Scanning Tunneling Microscopy

Surface alloys attract great interest due to their exotic properties. However, many experiments lack specific research studies on the formation process of surface alloys and the evolution of subsequent structures. Here, via scanning tunneling microscopy, we investigate the surface structure evolution of Sb on Ag(110) as a function of coverage (denoted as θ). At a low coverage (θ ≤ 0.5 ML), the deposited Sb atoms were incorporated into the topmost layer of Ag(110), forming the AgSb surface alloy confined to the surface and the c-(2 × 2) alloy islands supported on Ag(110). As the coverage increases (θ > 0.5 ML), chain structures begin to appear at the edge of AgSb alloy islands. When θ increases to a certain extent, the surface is completely transformed into nanostrips along the [001] direction, and no new structure appears with θ up to 5 ML. In addition, we also proposed a possible atomic structure model of the chains and strip structure. Our work is a great help for understanding the specific properties of the surface alloy layer.