Calculations of Oxygen Adsorption-Induced Surface Reconstruction and Oxide Formation on Cu(100)

Abstract

The energetics and kinetics of the missing-row reconstruction (MRR) and missing-row island formation on the Cu(100) surface are investigated using density functional theory calculations. We find that copper ejection from the c(2 × 2) surface is made energetically possible by the presence of surface-adsorbed O2 molecules. The barrier for MRR formation via this ejection mechanism is calculated to be 0.96 eV, consistent with the experimentally observed formation temperature of 400 K. The reaction pathways between Cu and O2 result in the formation of Cu–O chains on the c(2 × 2) surface, which can grow from the −O–Cu–O– trimer at least up to the −Cu–O–Cu–O–Cu– pentamer. Remarkably, these chains can both diffuse rapidly and change their orientation on the surface, allowing them to assemble into longer Cu–O chains. Facile diffusion of the Cu–O chains occurs via a collective mechanism which limits the number of broken Cu–O bonds. Perpendicular to the Cu–O rows, the chains hop first at one end and then the other. ...