近化学计量比钽酸锂晶体的拉曼光谱研究

本文研究了不同组分钽酸锂晶体的拉曼散射光谱,我们发现,在谱线的形状和数量方面,近化学计量比晶体与同成分晶体存在明显差异.通过实验,我们得到了钽酸锂晶体完整的长波长光学模式,并首次给出了钽酸锂晶体拉曼线宽和晶体组分的定量关系.另外,我们还发现了两个与本征缺陷相关的局域模,278cm-1和750cm-1峰,它们的强度与晶体中本征缺陷的数量成正比.

Study on Raman Spectrum of Near-stoichiometry Lithium Tantalate

The Raman scattering spectra of lithium tantalate crystals with different compositions were investigated.The comparison of the Raman data obtained for the congruent and the near-stoichiometric crystals reveals some differences in the shape and the number of Raman peaks,which lead to a new assignment of the long-wavelength optical phonons.And quantitative relationships between the linewidth of Raman peaks(142cm-1 for E-phonon and 861cm-1 for A1-phonon) and the crystal composition were firstly presented.Two local Raman lines, 278cm-1 and 750cm-1,were found for the congruent crystals and attributed to the intrinsic defects,Li vacancy and anti-site Ta ion,respectively.