拉曼光谱
声子
物理
拉曼散射
凝聚态物理
相变
结晶学
光学
化学
作者
Xiaoli Ma,Peng-Jie Guo,Changjiang Yi,Qiao-He Yu,Anmin Zhang,Jianting Ji,Yong Tian,Feng Jin,Yiyan Wang,Kai Liu,Tian‐Long Xia,Youguo Shi,Qingming Zhang
出处
期刊:Physical review
[American Physical Society]
日期:2016-12-13
卷期号:94 (21)
被引量:78
标识
DOI:10.1103/physrevb.94.214105
摘要
We comparably performed polarized Raman scattering studies of $\mathrm{MoT}{\mathrm{e}}_{2}$ and $\mathrm{WT}{\mathrm{e}}_{2}$. By rotating crystals to tune the angle between the principal axis of the crystals and the polarization of the incident/scattered light, we obtained the angle dependence of the intensities for all the observed modes, which is perfectly consistent with careful symmetry analysis. Combining these results with first-principles calculations, we clearly identified the observed phonon modes in the different phases of both crystals. Fifteen Raman-active phonon modes $(10\phantom{\rule{0.16em}{0ex}}{A}_{g}+5\phantom{\rule{0.16em}{0ex}}{B}_{g})$ in the high-symmetry phase $1{T}^{\ensuremath{'}}\text{\ensuremath{-}}\mathrm{MoT}{\mathrm{e}}_{2}$ (300 K) were well assigned, and all the symmetry-allowed Raman modes $(11\phantom{\rule{0.16em}{0ex}}{A}_{1}+6\phantom{\rule{0.16em}{0ex}}{A}_{2})$ in the low-symmetry phase ${T}_{d}\text{\ensuremath{-}}\mathrm{MoT}{\mathrm{e}}_{2}$ (10 K) and 12 Raman phonons $(8\phantom{\rule{0.16em}{0ex}}{A}_{1}+4\phantom{\rule{0.16em}{0ex}}{A}_{2})$ in ${T}_{d}\text{\ensuremath{-}}\mathrm{WT}{\mathrm{e}}_{2}$ were observed and identified. The present paper provides basic information about the lattice dynamics in transition-metal dichalcogenides and may shed some light on the understanding of the extremely large magnetoresistance in this class of materials.
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