中国物理B ›› 2015, Vol. 24 ›› Issue (7): 77104-077104.doi: 10.1088/1674-1056/24/7/077104

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Electronic and optical properties of lithium niobate under high pressure: A first-principles study

桑丹丹a, 王庆林b, 韩崇a, 陈凯a, 潘跃武a   

  1. a Mathematics and Physical Sciences Technology, Xuzhou Institute of Technology, Xuzhou 221008, China;
    b Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China
  • 收稿日期:2014-11-11 修回日期:2015-02-06 出版日期:2015-07-05 发布日期:2015-07-05
  • 基金资助:
    Projects supported by the National Natural Science Foundation of China (Grant Nos. 11347154 and 51172194) and the Foundation of Xuzhou Institute of Technology, China (Grant No. XKY2013203).

Electronic and optical properties of lithium niobate under high pressure: A first-principles study

Sang Dan-Dan (桑丹丹)a, Wang Qing-Lin (王庆林)b, Han Chong (韩崇)a, Chen Kai (陈凯)a, Pan Yue-Wu (潘跃武)a   

  1. a Mathematics and Physical Sciences Technology, Xuzhou Institute of Technology, Xuzhou 221008, China;
    b Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China
  • Received:2014-11-11 Revised:2015-02-06 Online:2015-07-05 Published:2015-07-05
  • Contact: Wang Qing-Lin, Han Chong E-mail:wangql@hpstar.ac.cn;hanchongxz@163.com
  • Supported by:
    Projects supported by the National Natural Science Foundation of China (Grant Nos. 11347154 and 51172194) and the Foundation of Xuzhou Institute of Technology, China (Grant No. XKY2013203).

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摘要： We theoretically study the structural, electronic, and optical properties of lithium niobate under pressure using the plane-wave pseudopotential density functional theory by CASTEP code. It was found that there is a phase transition from the R3c structure to the Pnma structure at a pressure of 18.7 GPa. The Pnma structure was dynamically stable according to the calculation of phonon dispersion. From the charge density distributions, there exist covalent interactions along the Nb–O bond. The hybridization between O 2p and Nb 4d orbital in the Pnma phase increases with increasing pressure, while it is not changed in the R3c phase. With increasing pressure, the average Nb–O bond length decreases and the Nb–O bond population increases, indicating the increased covalent character between Nb and O atoms under high pressure at Pnma phase, which leads to the increased hybridization between O 2p and Nb 4d orbitals. Furthermore, the optical dielectric function, refractive index, extinction coefficient, electron energy, loss and reflectivity are calculated.

关键词: pressure, electronic structure, optical properties, hybridization

Abstract: We theoretically study the structural, electronic, and optical properties of lithium niobate under pressure using the plane-wave pseudopotential density functional theory by CASTEP code. It was found that there is a phase transition from the R3c structure to the Pnma structure at a pressure of 18.7 GPa. The Pnma structure was dynamically stable according to the calculation of phonon dispersion. From the charge density distributions, there exist covalent interactions along the Nb–O bond. The hybridization between O 2p and Nb 4d orbital in the Pnma phase increases with increasing pressure, while it is not changed in the R3c phase. With increasing pressure, the average Nb–O bond length decreases and the Nb–O bond population increases, indicating the increased covalent character between Nb and O atoms under high pressure at Pnma phase, which leads to the increased hybridization between O 2p and Nb 4d orbitals. Furthermore, the optical dielectric function, refractive index, extinction coefficient, electron energy, loss and reflectivity are calculated.

Key words: pressure, electronic structure, optical properties, hybridization

中图分类号:  (Other inorganic compounds)

  • 71.20.Ps
74.25.Gz (Optical properties)