We report on the study of far-infrared transmission in silicon carbide of 6H polytype in the region of IR active folded transverse acoustic (FTA) phonon doublet. Joint analysis of the transmittance spectra obtained at low and high resolutions is performed to determine spectral dependences of the refractive index and absorption coefficient. A dual Lorentz oscillator model is used to simulate the FTA phonon contributions to the dielectric function. The oscillator strengths and phonon lifetimes for both the components of the FTA phonon doublet in 6H-SiC are determined. At temperature decrease from 300 to 5 K, the FTA phonon lifetimes increase more than six times, while the oscillator strengths remain the same.

中文翻译：

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6H-SiC中折叠横向声子双峰的光学通路

我们报告了 6H 多型碳化硅在红外有源折叠横向声学 (FTA) 声子双峰区域的远红外传输研究。对在低分辨率和高分辨率下获得的透射光谱进行联合分析，以确定折射率和吸收系数的光谱依赖性。双洛伦兹振荡器模型用于模拟 FTA 声子对介电函数的贡献。确定了 6H-SiC 中 FTA 声子双峰的两个组件的振荡器强度和声子寿命。当温度从 300 降低到 5 K 时，FTA 声子寿命增加了六倍以上，而振荡器强度保持不变。