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Analysis thermodynamic properties of intrinsic point defects in Y2O3 crystal based on the First-Principle

DOI：10.13255/j.cnki.jusst.20190217002

 作者 单位 E-mail 王炳佳 上海理工大学 理学院, 上海 200093 刘廷禹 上海理工大学 理学院, 上海 200093 liutyyxj@163.com 姚君涛 上海理工大学 理学院, 上海 200093

通过第一性原理计算软件VASP和晶格动力学软件GULP对氧化钇晶体中的晶格常数、振动熵、热力学跃迁能级和本征点缺陷形成能进行模拟计算，在考虑晶格振动熵贡献的情况下，得到空位、填隙以及反位的缺陷形成能与温度和氧偏压之间的变化关系。计算结果表明，当压强一定时，随着温度的不断升高，价带顶附近最稳定的缺陷为${\rm{Y}}_{\rm{i}}^{ {\text{·\!\!\!·\!\!\!·}} }$，导带底附近最稳定的缺陷由${\rm{V}}_{\rm{Y}}^{'''}$过渡到${\rm{O}}_{\rm{i}}^{''}$。计算结果还表明，可利用改变温度和控制氧偏压来调节氧空位的类型和浓度。给出了点缺陷随环境条件变化的二维、三维分布图，可为晶体生长和退火环境的选取提供理论依据。

The lattice constant, vibration entropy, thermodynamic transition energy level and intrinsic point defect formation energy in Y2O3 crystal were studied by computer simulations with VASP and GULP softwares. Considering the contribution of lattice vibration entropy, the formation energy of defects in the form of vacancies, interstitial and antisite with the changes in temperature and oxygen partial pressure was investigated. The results show that with the increase of temperature and oxygen partial pressure, the most stable defects near the top of the valence band is ${\rm{Y}}_{\rm{i}}^{ {\text{·\!\!\!·\!\!\!·}}}$, and the most stable defect near the bottom of the conduction band changes from ${\rm{V}}_{\rm{Y}}^{'''}$ to ${\rm{O}}_{\rm{i}}^{''}$. The calculations also prove that the type and concentration of oxygen vacancies can be adjusted by varying the temperature and controlling the oxygen partial pressure. In addition, the point defects distribution varying with environmental conditions was clearly presented by using two and three dimensional diagrams, which provides the theoretical basis for crystal growth and annealing environment selection.
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