Flat-surface-assisted and self-regulated oxidation resistance of Cu(111)

This is the authors' abstract. We don't add key points for this paper.

The formation of an ultraflat surface on copper thin films is important for suppressing the oxidation process, but the formation of multi-atomic steps and terraces is a result of the basic atomic stacking process and difficult to avoid. Here, we develop an innovative strategy for fabricating copper thin films with a semi-permanently oxidation-resistant surface. Comprehensive atomic-resolution microscopy reveals that our thin film consists mostly of flat surfaces and occasional mono-atomic steps. Our first principles calculations show that a mono-atomic step edge is as impervious as a flat surface to oxygen consistent with our experimental observations. Furthermore, the first principles calculations exhibit self-regulated oxidation resistance at the top surface layer: when the oxygen coverage of fcc sites of the surface exceeds 50%, the adsorbed oxygens on the top layer suppresses further adsorption of additional O atoms and renders the ultraflat Cu surface to be more oxidation resistant.