摘要
采用基于密度泛函理论的第一性原理方法,研究了由^(2)BaTiO_(3)/^(1)SrTiO_(3)/^(1)CaTiO_(3)所构成的超晶格材料的纵向挠曲电系数。构建了三种超晶胞构型,钛酸钡、钛酸锶和钛酸钙的层数比都为2:1:1,并且保持超晶胞的总层数为16层。对三种超晶胞构型,分别施加余弦应变,分析超晶格中各原子的位移和应变,以及每种构型的纵向挠曲电系数。结果表明,构型Ⅱ的纵向挠曲电系数可达5.63 nC/m,比单晶BaTiO_(3)、单晶SrTiO_(3)材料分别提升了16倍和6倍。本文的研究结果对遴选纵向挠曲电系数的材料具有较好的指导意义。
Composite materials with high flexoelectricity have attracted more and more research interests due to size effect.Even though the transverse and shear flexoelectric coefficients for heterostructures and superlattices are greater than those of constituent compounds,the longitudinal flexoelectric coefficient is almost as same as its constituent compounds.In this paper,the longitudinal flexoelectric coefficient of^(2)BaTiO_(3)/^(1)SrTiO_(3)/^(1)CaTiO_(3)superlattice with three different configurations,which are composed of alternating atomic layers of BaTiO_(3),SrTiO_(3)and CaTiO_(3)with the unit-thickness ratio between constituent compounds as 2:1:1,has been studied by first-principles based on density of function theory.Each configuration of superlattice has 16-unit-cell in thickness.The results demonstrate that the longitudinal flexoelectric coefficient of the 2nd configuration is 5.63 nc/m,which is 16 times and 6 times larger than those of constituent compounds(BaTiO_(3)and SrTiO_(3)),respectively.It provides a potential method for the fabrication of perovskite superlattice with better longitudinal flexoelectricity.
作者
陈许敏
王越昊
叶盼
王继光
CHEN Xumin;WANG Yuehao;YE Pan;Wang Jiguang(School of Sciences,Hangzhou Dianzi University,Hangzhou Zhejiang 310018,China)
出处
《杭州电子科技大学学报(自然科学版)》
2023年第5期90-95,共6页
Journal of Hangzhou Dianzi University:Natural Sciences
基金
国家自然科学基金资助项目(11874011)。
关键词
第一性原理
超晶格
纵向挠曲电系数
波恩有效电荷
first-principles
superlattice
longitudinal flexoelectric coefficient
Born effective charge