人工晶体学报2025，Vol.54Issue(9)：1584-1592,9.DOI:10.16553/j.cnki.issn1000-985x.2025.0068
KNbO3高压下相变行为的第一性原理研究
First-Principles Study on the Phase Transition Behavior of KNbO3 under High Pressure
摘要
Abstract
To gain a comprehensive understanding of the phase transition behavior of perovskite oxide KNbO3 under high pressure conditions,and provide crucial parameters for the engineering applications of ferroelectric materials under extreme conditions,a first-principles method based on density functional theory was employed in this study.The structural phase transitions,elastic properties,and electronic properties of KNbO3 under high pressure were systematically investigated at absolute zero(0 K).The results indicate that the most stable structure of KNbO3 is the orthorhombic Amm2 structure at zero pressure.The material exhibits ductility and is characterized as a central-force solid.Within the pressure range from 0 GPa to 50 GPa,KNbO3 undergoes two phase transitions:from the Amm2 structure to the tetragonal P4mm structure under 7.7 GPa,and from the P4mm structure to the trigonal R3mR structure under 10.1 GPa.Both phase transitions are accompanied by volume changes and are classified as first-order phase transitions.Elastic analysis reveals that KNbO3 transitions from ductility to brittleness during the phase transitions and exhibits significant elastic anisotropy.Band structure analysis shows that the band gap of the Amm2 structure under zero pressure is 2.125 eV,indicating an indirect band gap semiconductor.As pressure increases,the band gap initially decreases and then increases.This study not only enriches the understanding of the phase transition behavior of KNbO3,but also provides theoretical support for the design and application of new KNbO3 materials.关键词
KNbO3/第一性原理/密度泛函理论/结构相变/弹性性质/电子性质Key words
KNbO3/first-principle/density functional theory/structural phase transition/elastic property/electronic property分类
数理科学引用本文复制引用
冷昊宁,孙霄霄,穆柏旭,宁丽娜..KNbO3高压下相变行为的第一性原理研究[J].人工晶体学报,2025,54(9):1584-1592,9.基金项目
牡丹江师范学院科学技术研究一般项目(YB2021002) （YB2021002）
牡丹江师范学院横向课题(2202224008) （2202224008）
