晶格和A位离子的尺寸效应对ATiO_(3)型晶体晶格稳定性的影响  

Effect of size effect of lattice and A-site ions on lattice stability of ATiO_(3)-type crystals

作　　者：罗秋妮 成鹏飞[1] 党子妍 LUO Qiuni;CHENG Pengfei;DANG Ziyan(School of Science,Xi’an Polytechnic University,Xi’an 710048,China)

机构地区：[1]西安工程大学理学院,陕西西安710048

出　　处：《纺织高校基础科学学报》2023年第1期72-79,共8页Basic Sciences Journal of Textile Universities

基　　金：国家自然科学基金(51277138);陕西省自然科学基础研究计划项目(2021JM-442)。

摘　　要：研究钙钛矿晶体离子之间相互作用、相对振动与晶格稳定性的内在联系。针对典型钙钛矿晶体结构相同而相变差异显著的现象,采用第一性原理软件Castep,分析了晶格尺寸、A位离子尺寸各异系列简单钙钛矿晶格的声子谱和电子结构,揭示了离子之间化学键对离子相对振动的关键性作用,解释了晶格尺寸效应和A位离子尺寸效应。计算结果显示:A离子声子频移主要取决于A—O之间离子键属性,而Ti、O的声子频移主要取决于Ti—O之间共价键属性;减小晶格尺寸和增大A位离子尺寸有助于晶体的稳定性。为基于晶格调控优化钙钛矿的物理化学性能提供了新思路。The relationship of the interaction, relative vibration and lattice stability of perovskite crystals was studied. In view of the phenomenon that typical perovskites have the same crystal structure but significant difference in phase transformation, this paper uses first-principles software Castep to analyze phonon spectrum and electronic structure of a series of simple perovskite crystal lattice with different lattice sizes and A-position ion sizes, revealing the key role of chemical bonds between ions on the relative vibration of ions. Lattice size effect and A-site ion size effect are explained. The results show that the phonon frequency shift of A ion mainly depends on the ionic bond property between A and O, while the phonon frequency shift of Ti and O mainly depends on the covalent bond property between Ti and O. Reducing the lattice size and increasing the size of A ion are conducive to the stability of crystal. It provides a new idea to optimize the physical and chemical properties of perovskite based on lattice regulation.

关 键 词：钙钛矿 声子谱 电子结构 软模 态密度 

分 类 号：O469[理学—凝聚态物理]