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-Nov-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: 
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