Alkaline-earth and Rare-earth Elements and Oxygen Vacancy in BaTiO_3: Analyses by First-principles Calculations and EXAFS

摘要

We performed first-principles calculations to examine the interaction among rare-earth (RE), alkaline-earth (AE) elements and oxygen vacancy (Vo) in BaTiO_3, in order to clarify the combined effects of V_o trapping by two different elements. It was found that there is a synergistic effect of Vo trapping by RE at Ba site and AE at Ti site, so that the co-doping is effective to improve insulating reliability of BaTiO_3. We also verified that the local atomic structures around dopants obtained by calculations well agree with that obtained experimentally by extended X-ray absorption fine structure (EXAFS) analyses. The present work is the first one to clarify the structural environment around dopants including Vo by both theoretical and experimental approaches.