Electric field tuning of oxygen stoichiometry at oxide surfaces: molecular dynamics simulations studies of zirconia

摘要: Ultra-thin metal-oxides such as zirconia have tremendous technological applications electrolyte membranes for advanced solid oxide fuel cells, cladding material light water nuclear reactors, pressure tube materials heavy reactors and corrosion resistant coatings. Oxide non-stoichiometry is an important factor which significantly affects their functional properties applicability. Here, we report on the ability to athermally control oxygen in ultra-thin films through local electric field perturbations from simulations. Variable charge molecular dynamics simulations indicate enhanced oxidation kinetics Zr (0001) substrate presence of field. Natural with no resulted amorphous scale a self limiting thickness ∼10 A increased ∼17–26 applied fields 1–10 MV/cm. Electric (∼107 V/cm) lowers activation energy barrier ionic migration film leads incorporation into film. Activation decreased 1.13 eV 0.08 10 This manifests itself form dramatic density stoichiometry improvements grown film, indicated by calculated structural dynamical correlation functions. (O/Zr ratio) natural was 1.42 indicative sub-stoichiometric deficient near stoichiometric value 1.86 MV/cm assisted oxidation. The simulation findings agree well previously reported experimental observations. Our results demonstrate pathway concentration near-surface regions that great importance technologies utilizing oxides ranging catalysis, electronic device technologies.