计算物理 ›› 2015, Vol. 32 ›› Issue (4): 487-495.

• 论文 • 上一篇    下一篇

BaTiO3/SrTiO3(1:1)有序超晶格的第一性原理研究

王江舵, 代建清, 牛之慧, 张虎, 宋玉敏   

  1. 昆明理工大学材料科学与工程学院, 昆明 650093
  • 收稿日期:2014-07-21 修回日期:2014-12-08 出版日期:2015-07-25 发布日期:2015-07-25
  • 作者简介:王江舵(1987-),男,硕士生,主要从事材料的第一性原理研究,E-mail:373867984@qq.com
  • 基金资助:
    国家自然科学基金(51162019,51462019)资助项目

BaTiO3/SrTiO3(1:1) Superlattice

WANG Jiangduo, DAI Jianqing, NIU Zhihui, ZHANG Hu, SONG Yumin   

  1. School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China
  • Received:2014-07-21 Revised:2014-12-08 Online:2015-07-25 Published:2015-07-25

摘要: 用第一性原理计算研究沿[110]和[111]方向有序的BaTiO3/SrTiO3(BTO/STO)1:1超晶格的晶格动力学、介电和压电性能.对两种有序BTO/STO超晶格从最高对称性的结构出发计算布里渊区中心声子,通过冻结不稳定声子得到畸变结构,进一步冻结不稳定声子得到基态结构.两种有序BTO/STO超晶格的基态结构分别是Pm和R3m结构.把声子介电张量和内应变压电张量分解成单个离子和单个声子的贡献.根据离子对介电和压电张量各分量的贡献可知Ti和O离子对介电和压电有比较大的贡献.声子对介电和压电张量的贡献的分析果表明频率较低的声子有主要的贡献.特别是沿[110]方向有序BTO/STO超晶格中ε11主要来自于频率为49 cm-1的软模A'声子的贡献.

关键词: 第一性原理, BaTiO3/SrTiO3, 介电, 压电

Abstract: Lattice dynamics,electronic and lattice contributions to dielectric and piezoelectric responses of BaTiO3/SrTiO3(1:1)(BTO/STO 1:1) 10-atom superlattice with Ba/Sr [110] and [111] ordering were investigated with first-principles calculations. We explored ground structure from the highest phase by successively freezing in unstable polar modes. We found that ground structure are in Pm and R3m symmetry,respectively. Lattice contributions to dielectric and piezoelectric tensor coming from individual atoms and individual modes were explored. O and Ti atoms provide extraordinary great contribution to lattice dielectric and piezoelectric responses. On the other hand,great dielectric and piezoelectric tensor are mainly due to low frequency phonons. Especially,for BTO/STO(1:1)superlattice with Ba/Sr [110] ordering,ε11is mainly due to A' phonons with ωλ=49 cm-1.

Key words: first-principle, BaTiO3/SrTiO3, dielectric, piezoelectric

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