First-principles study of diffusion behaviour of point defects in the O-terminated (0001) surface in wurtzite ZnO

A detailed first-principles study of the diffusion behaviour of point defects in the O-terminated （0001） surface in wnrtzite ZnO was performed. The 0 vacancy and interstitial are found to diffuse much more easily in surface than in bulk. The Zn vacancy has a similar migration barrier for both bulk and surface, but has much smaller barrier for the diffuse-in process. The Zn interstitial is difficult to diffuse in the surface directly, but it can diffuse into the bulk relatively easily. Specific values of corresponding migration barriers are obtained.

Adsorptions and diffusions of carbon atoms on the surface and in the subsurface of Co(200): A first-principles density-functional study

First-principles calculations based on density functional theory are used to investigate the adsorptions and diffusions of carbon atoms on the surface and in the subsurface of Co （200）. The preferred site for the carbon atom on the surface is the hollow site, and the preferred site in the subsurface is the octahedral site. There is charge transfer from the surface to the adsorbed carbon atom, and for the most favorable adsorbed structure the charge transfer is largest. Moreover, the energy barriers for the diffusions of carbon atoms on the surface and from the surface into the subsurface and then back to the surface are calculated in detail. The results indicate that the energy barrier for the diffusion of carbon atoms on the surface is comparable to that from the subsurface to the surface. The results imply that both the direct surface nucleation and the surface segregation from Co bulk can be observed in the chemical vapor deposition growth of graphene on Co （200） substrate, which can gain a new insight into the growth mechanism of graphene.

Adsorption and diffusion of oxygen on metal surfaces studied by first-principle study:A review

First-principle calculations,especially by the density functio nal theory(DFT),is used to study the structure and properties of oxygen/metal interfaces.Adsorption of oxygen molecules or atoms on metal surfaces plays a key role in surface science and technology.This review is dedicated to the adsorption of oxygen molecules or atoms on metal surfaces and diffusion behavior from first-principle investigation.We hope that this review can provide some useful contributions to understa nd the study of adsorption properties and diffusion behavior on a metal surface at an atomic-scale,especially for those interested in catalytic oxidation and application of corrosion.