First-principles study of the surfaces of zirconium during early stages of metal oxidation

Abstract

The surfaces of zirconium during early stages of metal oxidation were examined by first-principles calculations using density functional theory. DFT calculations suggested that the interaction between the oxide and the substrate induced a slight vertical contraction of the oxide film and a slight buckling of the Zr layer in the oxide in which the latter effect was found to be more important. The total effect was significant. In fact, among the three examined configurations, the difference in heights across the oxide surface could reach 0.55 [angstroms] which should be visible under STM images. Therefore, the periodic relaxation patterns observed on the surface of zirconium at the initial stage in of its oxidation in previous study could be explained by the buckling of the zirconium layer in the oxide coupled with the fact that there was a mismatch between Zr metal and ZrO2 oxide lattice parameters. While some atomically-resolved STM images were also generated, more DFT results from different structure configurations are needed before a complete and useful large-scale STM image could be constructed.