PNNL

Abstract

The structure and mechanisms of bonding and defect formation at the interfaces between amorphous silica (a-SiO2) and BaTiO3(0 0 1) were investigated using ab initio molecular dynamics. It was found that the nature of interfacial bonds crucially depends on the BaTiO3 surface termination. In particular, the interface between silica and TiO2-terminated BaTiO3 (BTO) slab is characterised by strong covalent Ti–O–Si bonds, while the interface between silica and BaO-terminated BTO demonstrates ionic character of interfacial bonds and exhibits bond instability. In both cases, the dynamics of oxygen species at oxide interfaces is a driving force of the formation of interfacial bonds and defects.