锐钛矿型TiO2(101)面本征点缺陷的理论研究

采用平面波超软赝势方法计算了锐钛矿型TiO₂(101)面存在本征空位和间隙点缺陷的几何结构以及缺陷形成能.首先分析了点缺陷对表面结构的影响，发现不同类型缺陷导致缺陷周围原子有不同的位移趋势：O空位的产生导致空位周围的Ti原子向空位外移动，Ti₁和Ti₂空位的产生均使O₁自发地与周围的O原子团聚，O_i原子易被周围的氧原子吸附而成键，而Ti_i2缺陷几乎 关键词： 第一性原理 2')" href="#">TiO₂ 点缺陷 表面结构

Theoretical study of native point defects on anatase TiO2 (101) surface

First-principles plane-wave pseudopotential calculations were performed to study the energetics and the geometical structures of intrinsic vacancies and interstitials on the anatase TiO₂ (101) crystal surface. Firstly，we analyzed the effects of point defects on the geometrical structures. For the O vacancy，all the nearest-neighbor Ti atoms move away from the vacancy toward the other O neighborhood. As Ti₁ or Ti₂ is missing here，O₁ atom spontaneously and strongly binds with nearest-neighbor O on the lattice site to form an O₂ molecule. The results also show that interstitial Ti_i2 affects little host lattice and the interstitial O_i would spontaneously bind to lattice oxygen. By investigating the calculated defect formation energies，we found that under the O-rich condition，the V_Ti1 and O_i formation are favorable，however，under the Ti-rich condition，although the point defects of Ti_i2 and V_O1 easily appear，the formation energy of the Ti_i2 is lower than that of the V_O1. Finally，to determine the relative stability of the point defects，the formation enthalpies of several point defects were considered.