First-principles molecular-dynamics simulation of proton diffusion in perovskite oxides

The microscopic mechanism of the proton diffusion in protonic conductors, S c-doped SrTiO3 and Y-doped SrCeO3, is studied by a first-principles molecul ar-dynamics simulation. It is found that the proton forms an O-H bond with the neighboring O ion, and that the frequency of the O-H stretching vibrati on depends on the position of the proton in these crystals. It is shown tha t the position dependence of the O-H stretching vibration is induced by the presence of doped acceptor ions. (C) 1998 Published by Elsevier Science B. V. All rights reserved.