锆酸锶材料能带结构的第一性原理研究

First-principles study of the electronic band structure of strontium zirconate

采用广义梯度近似下的密度泛函理论的全势线性缀加平面波方法,精确计算了钙钛矿材料SrZrO3立方相、正交相的电子结构.计算结果表明,SrZrO3立方相、正交相都是直接带隙,对带隙起主要作用的是Zr的4d态和O的2p态,它们的大小分别为3.53,3.72 eV.SrZrO3由立方相到正交相时Sr—O和Zr—O之间的杂化增强,间接增强了ZrO6八面体的畸变,降低了体系的总能量,有利于正交相的稳定.

The electronic band structures of both the cubic and orthorhombic SrZrO3 are calculated using an accurate fullpotential linearized augmented plane-wave method and implementing the local-orbital basis functions within the generalized gradient approximation.The calculated results show that the band gaps for the cubic and orthorhombic phase are both the directband gap,corresponding to the values about 3.53 and 3.72 eV,respectively.In both cubic and orthorhombic SrZrO3,the valence band is mainly composed of O 2p states,and the conduction band mainly consists of Zr 4d states.From the cubic to orthorhombic phase,the Sr—O and Zr—O hybridization is strengthened,which enhances the distortion of ZrO6 octahedron and reduces the total energy of the system,in favor of stabilizing the orthorhombic phase structure of SrZrO3.