Effect of O2 adsorption on electron scattering at Cu(001) surfaces

Abstract

The electrical resistance of epitaxial Cu(001) sequentially increases, decreases, and again increases when exposed to ${10}^{-3}–{10}^5\text{Pa}\text{s}$ of ${\text{O}}_2$ . This is attributed to partial specular surface scattering for smooth clean Cu(001) and for the surface with a complete adsorbed monolayer, but diffuse scattering at partial coverage and after chemical oxidation. A model relates the surface coverage to the specularity parameter and finds adatom and advacancy scattering cross-sections of $0.8\pm 0.2$ and $0.06\pm 0.03{\text{nm}}^2$ , which are qualitatively validated by nonequilibrium ab initio transport simulations. The rates for resistance change are proportional to the ${\text{O}}_2$ partial pressure.