CAJ | 학술논문

基于密度泛函理论的缀加平面波方法计算了 HfO2的正交相 Pca21和四方相 P42/nmc,其中正交相具有铁电性质。计算结果表明,在晶体结构方面, HfO2正交相和四方相都具有类萤石结构特征,并且从四方相P42/nmc到正交相Pca21的转变过程中单胞变形<3.75%；在电子结构方面,通过四方相到正交相的结构转变,Hf的5d和O 的2p、2s的杂化效应增强,同时这些电子态向低能移动,使正交相的相对能量低于四方相。这些研究结果证实了 HfO2具有铁电性质的 Pca21正交相是一种稳定的相结构,并解释了从P42/nmc四方相到Pca21正交相的转变关系。
기우밀도범함이론적철가평면파방법계산료 HfO2적정교상 Pca21화사방상 P42/nmc,기중정교상구유철전성질。계산결과표명,재정체결구방면, HfO2정교상화사방상도구유류형석결구특정,병차종사방상P42/nmc도정교상Pca21적전변과정중단포변형<3.75%；재전자결구방면,통과사방상도정교상적결구전변,Hf적5d화O 적2p、2s적잡화효응증강,동시저사전자태향저능이동,사정교상적상대능량저우사방상。저사연구결과증실료 HfO2구유철전성질적 Pca21정교상시일충은정적상결구,병해석료종P42/nmc사방상도Pca21정교상적전변관계。
The Pca21 orthogonal phase with ferroelectric property and P42/nmc tetragonal phase of HfO2 have been studied using the augmented plane wave within density functional theory in this work.It has been found out that in the case of the crystal structures,both the ferroelectric phase and the tetragonal phase can be regar-ded as fluorite-related structure,and the deformation of the unit cells during transformation from the tetragonal phase to the ferroelectric phase was less than 3.75%;in the case of the electronic structures,the hybridization of Hf 5d and O 2p,2s was enhanced by the transformation from the tetragonal phase to the ferroelectric phase, and the electron states shift to lower energy,which lead to a lower lattice energy of the ferroelectric phase. These results have confirmed that the Pca21 orthogonal phase with ferroelectric property was a stable phase, and provided further insight into the transformation relationship between the ferroelectric phase and the tetra-gonal phase.