中文摘要：

采用基于密度泛函理论的第一性原理方法,研究了BaTiO3在四方相下的各种缺陷性质.计算结果表明,在富氧环境下,钛的中性氧空位、分肖特基缺陷2VTi^3-＋3VO^2＋形成能分别为最低;而当体系处在还原环境下时,氧空位逐渐成为主要缺陷,其形成能最低.由于四方相下存在较强的Ti—O键共价杂化,四方相下全肖特基缺陷V2Ba-＋VTi^4-＋3VO^2＋的形成能比立方相略高.这种共价杂化也与Ti弗伦克尔缺陷形成能有密切关系.此外,在计算肖特基缺陷形成能时,缺陷间的相互作用往往不可忽略.

英文摘要：

Based on density functional first principles method,the defect properties in tetragonal BaTiO3 have been studied. The results showed that the formation energies of neutral Ti vacancy and partial Schottky defect 2VTi^3-＋ 3VO^2 ＋are the lowest under oxygen-rich condition; while under reducing condition oxygen vacancy becomes the primary defect. The calculated full Schottky formation energy is higher than that obtained in the cubic phase,which may be the result of the strong hybridization between the Ti-O bonds. The hybridization is also responsible for the Frenkel formation energy of Ti. The defect-interactions are important when dealing with Schottky defects.