Negatively charged hydrogen at oxygen-vacancy sites in BaTiO3: Density-functional calculation

作者：Iwazaki Yoshiki^*; Suzuki Toshimasa; Tsuneyuki Shinji

来源：Journal of Applied Physics, 2010, 108(8): 083705.

DOI：10.1063/1.3483243

With a specific focus on defects formed from H atoms and oxygen vacancies (V-O) in perovskite-type oxide, stability and stable valence states of complex defects formation processes within BaTiO3 are studied by using first-principle density-functional theory calculations. In our findings, H atoms diffuse as protons (H+) into interstitial sites in BaTiO3, whereas these atoms when trapped at centers of VO sites convert to negatively ionized states (H-). We also find that H atom trapping at V-O sites occurs only in n-type carrier-rich environments without carrier compensation of V-O(2+) and H+. If carrier electrons are compensated, H+ ions are excluded from V-O(2+) sites due to the repulsive Coulomb potential existing between the H+ ion and the positively charged V-O(2+) site. Difficulties in the calculation of the diffusion-energy diagram for H atoms, involving essential changes in the stable valence states during the diffusion process, are discussed and a practical solution is presented.

• 出版日期2010-10-15