QUASIELASTIC LIGHT SCATTERING FROM RUTILE
QUASIELASTIC LIGHT SCATTERING FROM RUTILE
复制标题
金红石的准弹性光散射
DOI：
10.1103/physrevb.60.12730
复制
发表时间：
1999
影响因子：
3.7
通讯作者：
M. Grimsditch
中科院分区：
文献类型：
--
作者：
A. Koreeda;M. Yoshizawa;S. Saikan;M. Grimsditch
在金红石（TiO{sub 2}）单晶中观察到由两个分量组成的准弹性光散射。在297 K时线宽为330 GHz的宽谱分量随温度的降低而变窄。与此相反，在297 K时线宽为1.1 GHz的窄分量随着温度的降低而变宽。我们提出了一个统一的解释，这是基于双声子差拉曼散射。对于窄组分，它将被证明，从一个{italsingle}声学声子分支的双声子差过程解释的强度和波矢的依赖性的温度依赖性的线宽在低温下。熵波动散射方面的传统解释也试图为200 K以上的温度，声子碰撞发生更频繁地比在较低的温度和声子系统可以被认为是流体动力学。对于宽分量，从{italdifferent}声子分支的双声子差散射将被证明提供一个很好的解释的温度依赖的强度。此外，线宽的温度依赖性和它的不敏感性的散射波矢的变化也解释了与此模型。{版权} {美国物理学会}
Quasielastic light scattering consisting of two components has been observed in single crystals of rutile (TiO{sub 2}). The broad component with a linewidth of 330 GHz at 297 K becomes narrower with decreasing temperature. In contrast, the narrow component, which has a linewidth of 1.1 GHz at 297 K, broadens as the temperature decreases. We present a unified explanation for both components, which is based on two-phonon difference Raman scattering. For the narrow component, it will be shown that two-phonon difference processes from a {ital single} acoustic phonon branch explain the temperature dependence of the intensity and the wave vector dependence of the linewidth at low temperatures. The conventional explanation in terms of entropy-fluctuation scattering is also attempted for temperatures above 200 K where phonon collisions occur more frequently than at lower temperatures and the phonon system may be considered hydrodynamically. For the broad component, two-phonon difference scattering from {ital different} phonon branches will be shown to provide a good explanation for the temperature dependent intensity. Furthermore, temperature dependence of the linewidth and its insensitivity to changes in scattering wave vector are also explained with this model. {copyright} {ital 1999} {ital The American Physical Society}