计算物理 ›› 2011, Vol. 28 ›› Issue (1): 111-118.

• 研究论文 • 上一篇    下一篇

金红石→萤石TiO2相变的第一性原理计算

周志坚1, 胡燕飞1,2   

  1. 1. 四川理工学院理学院, 四川 自贡 643000;
    2. 四川大学原子与分子物理研究所, 四川 成都 610065
  • 收稿日期:2009-12-02 修回日期:2010-05-17 出版日期:2011-01-25 发布日期:2011-01-25
  • 作者简介:周志坚(1965-),male,Sichuan,associate professor,engaged in theoretical physics.

First-principles Study of Rutile-to-Fluorite Transition

ZHOU Zhijian1, HU Yanfei1,2   

  1. 1. School of Science, Sichuan University of Science & Engineering, Zigong 643000, China;
    2. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
  • Received:2009-12-02 Revised:2010-05-17 Online:2011-01-25 Published:2011-01-25

摘要: 利用第一性原理平面波密度泛函理论并结合准谐德拜模型,对TiO2从金红石结构到萤石结构的相变进行理论研究.依据焓相等原理,得到TiO2从金红石结构到萤石结构的相变压强为45.32 GPa,并通过吉布斯能的计算发现相变压强随温度的增加而增加,运用拟合的方法估计实验条件下的相变压强(温度为1900-2100K时,Pt=47.604~47.756 GPa).运用等吉布斯能原理,得到零压下从金红石到萤石结构TiO2的相变温度为2029 K.计算结果与实验及其他理论值相符,并通过准谐德拜模型成功获得相变前后的结构和热力学性质,如相对体积、热膨胀系数、热容和德拜温度等.

关键词: TiO2, 热力学性质, 相变, 密度泛函理论, 准谐德拜模型

Abstract: Phase transition of TiO2 from rutile to fluorite is investigated with first principles plane-wave pseudopotential density functional theory,together with a quasi-harmonic Debye model.The rutile-to-fluorite(R-F) transition pressure and temperature obtained are 45.32 GPa and 2029 K,respectively,which are consistent with experimental and calculated results.The R-F transition pressure increase with increasing temperature.By fitting,we estimate transition pressure at experiment temperatures(T=1900-2 100 K,Pt=47.604-47.756 GPa).Moreover,dependences of relative volume V/V0 on pressure P,thermal expansion coefficient α and heat capacity cV on pressure P and temperature T are obtained.

Key words: TiO2, thermodynamic properties, transition phase, density functional theory, quasi-harmonic Debye model

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