Barrier effect of oxide on Cu permeation on Be surface

Cu-doped-Be capsule has become the international focus of ignition target design and preparation. The interaction between Be and dopants plays an important role in performances of a capsule. In this study, the barrier effect of oxide on Cu permeation on Be slab is studied using ab initio simulations based on van der Waals density-functional theory. We focus on the Cu permeation on both partial and perfect BeO slabs and construct two typical surface structures for the perfect BeO slab with Be-terminated and O-terminated, respectively. The results show that the diffusion of Cu atoms in Be is inhomogeneous and preferentially along the radial direction. We find that the BeO has a blocking effect on Cu atoms diffusion, and the disordered amorphous-like BeO can better impede the inhomogeneous diffusion than the perfect BeO. Furthermore, Cu atoms diffuse with more difficulty on a Be-terminated surface than on an O-terminated surface.