CAJ | 학술논문

利用第一性原理平面波赝势密度泛函理论方法对TiO2从金红石结构到萤石结构的相变进行了理论研究,并且通过准谐德拜模型分别得到了金红石和萤石结构TiO2的热力学性质.计算结果与实验值以及其它理论计算的结果都符合得很好,通过吉布斯能的计算得到TiO2从金红石结构到萤石结构的相变压强为47.74 GPa,并成功地获得了相对体积(V/Vo)、德拜温度(θ)和热容(Cv)随压强(p)和温度(T)的变化关系.
이용제일성원리평면파안세밀도범함이론방법대TiO2종금홍석결구도형석결구적상변진행료이론연구,병차통과준해덕배모형분별득도료금홍석화형석결구TiO2적열역학성질.계산결과여실험치이급기타이론계산적결과도부합득흔호,통과길포사능적계산득도TiO2종금홍석결구도형석결구적상변압강위47.74 GPa,병성공지획득료상대체적(V/Vo)、덕배온도(θ)화열용(Cv)수압강(p)화온도(T)적변화관계.
The phase transition of TiO2 from the rutile structure to the fluorite structure under pressure was investigated by the first principles plane-wave pseudopotential density functional theory method. The thermodynamic properties of the rutile and fluorite structures for TiO2 were obtained by the quasi-harmonic Debye model. The results obtained are in good agreement with the experimental data and other theoretical results. We found that the rutile-to-fluorite transition of TiO2 occurred at 47.74 GPa from the Gibbs energy calculations. Moreover, the dependence of the relative volume (V/V0), the Debye temperature (θ) and the heat capacity (Cv) on the pressure (p)as well as the heat capacity (Cv) on the temperature (T) were also successfully obtained.