Optical and Acoustic Vibrations Confined in Anatase TiO2 Nanoparticles under High-Pressure

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• 作者：L. Saviot ; D. Machon ; L. Debbichi ; A. Girard ; J. Margueritat ; P. Kr眉ger ; M. C. Marco de Lucas ; A. Mermet
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：May 15, 2014
• 年：2014
• 卷：118
• 期：19
• 页码：10495-10501
• 全文大小：352K
• 年卷期：v.118,no.19(May 15, 2014)
• ISSN：1932-7455

文摘

The effect of an applied high pressure on the optical and acoustic vibrations of small anatase TiO₂ nanoparticles is studied using Raman scattering. All the Raman peaks show a significant variation of their frequency with pressure, except for the low-frequency peak which is due to acoustic vibrations confined in the nanoparticles. These variations (or lack thereof) are compared to first-principles calculations of the stiffness tensor and phonons of bulk anatase TiO₂ as a function of pressure. In particular, the variation of the shape of the low-frequency peak is explained by the increase of the elastic anisotropy of anatase TiO₂ as pressure is increased.