Scattering of Surface States at Step Edges in Nanostripe Arrays

Surface states of noble metal surfaces split into Ag-like and Cu-like subbands in stepped Ag/Cu nanostripe arrays. The latter self-assemble by depositing Ag on vicinal Cu(111). Ag-like states scatter at nude step edges in Ag stripes, leading to umklapp bands, quantum size effects, and peak broadening. By contrast, Ag stripe boundaries become transparent to Cu-like states, which display band dispersion as in flat Cu(111). We find a linear relationship between the quantum size shift and peak broadening that applies in a variety of stepped systems, revealing the complex nature of step barrier potentials.