標題: | Size-dependent lattice dynamics of barium titanate nanoparticles |
作者: | Huang, Tung-Ching Wang, Mei-Tan Sheu, Hwo-Shuenn Hsieh, Wen-Feng 光電工程學系 Department of Photonics |
公開日期: | 28-十一月-2007 |
摘要: | By applying a single-tetragonal-phase model to refine the crystal structure and the coupled-phonon model to analyze transverse optical ( TO) modes of BaTiO3 nanocrystals, we found, upon decreasing the particle size from 140 to 30 nm, that the tetragonality of BaTiO3 nanocrystallites is reduced accompanied by expanding unit-cell volume, which is the dominant mechanism for reducing giant LO-TO splitting in the BaTiO3 system. The weakening coupling of two low-frequency modes among three A(1) ( TO) phonons leads to changing the lowest one from a spectral dip to a peak, whereas the increasing coupling strength between two high-frequency modes repels them farther so that there is less reduction in spectral separation. |
URI: | http://dx.doi.org/10.1088/0953-8984/19/47/476212 http://hdl.handle.net/11536/10098 |
ISSN: | 0953-8984 |
DOI: | 10.1088/0953-8984/19/47/476212 |
期刊: | JOURNAL OF PHYSICS-CONDENSED MATTER |
Volume: | 19 |
Issue: | 47 |
結束頁: | |
顯示於類別: | 期刊論文 |