Diffusion of oxygen atom near Zr(0001) surface

Abstract

Based on the density functional theory calculations， the diffusion of oxygen atoms near the Zr（0001）surface is studied by using the nudged elastic band method. Firstly， the active energy of diffusion of oxygen atoms from the surface face-centred cubic （SFCC） sites into surface hexagonal close-packed sites in Zr（0001） surface is calculated. The active energy for the diffusion is 0.77 eV. Secondly， the active energy of diffusion of oxygen atoms from the SFCC into octahedral interstitial sites between the second and third layers Octa（2，3） via octahedral interstitial sites between the first and second layers Octa（1，2） is calculated too. There are two energy barriers for oxygen atom to overcome. The active energies are 2.14 and 2.57 eV， respectively. As a result， the diffusion of oxygen atom above the Zr（0001） surface is easier than the diffusion into the subsurface.