高压下LiVO_(3)相变行为的第一性原理研究  

First-Principles Study on Phase Transition Behavior of LiVO_(3)under High Pressure

作　　者：冷昊宁 孙霄霄[1] 刘凤举[1] 赵祥敏[1] LENG Haoning;SUN Xiaoxiao;LIU Fengju;ZHAO Xiangmin(School of Physics and Electronic Engineering,Mudanjiang Normal University,Mudanjiang 157012,China)

机构地区：[1]牡丹江师范学院物理与电子工程学院,牡丹江157012

出　　处：《人工晶体学报》2024年第7期1222-1230,共9页Journal of Synthetic Crystals

基　　金：牡丹江师范学院科学技术研究一般项目(YB2021002)。

摘　　要：通过基于密度泛函理论的第一性原理计算方法讨论了0~90 GPa内LiVO_(3)的结构、弹性性质与电子性质。计算得知LiVO_(3)在基态下最稳定的结构为C 12/c 1。当压强在0~4.2 GPa时,C 12/c 1结构与C 1 c 1结构共同存在。压强在4.2 GPa时,材料会发生由C 12/c 1相到R 3 cH相的结构相变。通过弹性性质的计算得到零压下LiVO_(3)的体积模量、弹性模量、剪切模量分别为38、23、59 GPa,泊松比为0.24。材料为非中心力固体,呈现大的延展性,具有极大的弹性各向异性特性。电子结构的计算表明价带顶与导带底主要由O—V共价键作用,基态下C 12/c 1结构的LiVO_(3)是间接带隙半导体,带隙为3.016 eV。相变得到的R 3 cH结构是间接带隙半导体,带隙为2.56 eV,相变后电子更容易发生跃迁,明显改善了材料的导电性质。The structure,elastic properties and electronic properties of LiVO_(3)within the pressure range of 0 to 90 GPa were discussed using first-principles calculation method based on density functional theory.The most stable structure of LiVO_(3)at the ground state is C 12/c 1.When the pressure is between 0 GPa and 4.2 GPa,both C 12/c 1 and C 1 c 1 structure co-exist.Under the pressure of 4.2 GPa,the material undergoes a structural phase transition from the C 12/c 1 phase to the R 3 cH phase.The bulk modulus,elastic modulus and shear modulus of LiVO_(3)under zero pressure were calculated as 38,23,59 GPa,respectively,with a Poisson ratio of 0.24.The material is a non-central force solid,showing great ductility and great elastic anisotropy.The calculation of the electronic structure shows that the valence band top and conduction band bottom are mainly due to the covalent bonding between O and V.At the ground state,the C 12/c 1 structure of LiVO_(3)is an indirect band-gap semiconductor with a band gap of 3.016 eV.The R 3 cH structure is also an indirect bandgap semiconductor with a band gap of 2.56 eV,which means that electrons are more prone to transition,significantly improving the electrical conductivity of the materials.

关 键 词：LiVO_(3) 第一性原理 弹性性质 电子结构 结构相变 

分 类 号：O469[理学—凝聚态物理]