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
桑丹丹a, 王庆林b, 韩崇a, 陈凯a, 潘跃武a
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
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.
中图分类号: (Other inorganic compounds)