论文标题
压力引起的晶格扩展和层次中的声子软化$ res_2 $
Pressure induced lattice expansion and phonon softening in layered $ReS_2$
论文作者
论文摘要
我们报告了$ res_2 $样品上的高压X射线衍射和详细的系统拉曼测量结果，该样品是从单晶机械剥落的。观察到一些新的布拉格峰出现在6 GPA以上，表明从扭曲的$ 1T $到扭曲的$ 1T $$^{\ prime} $在Triclinic结构中的结构过渡。通过在相同压力范围内的新拉曼模式出现的外观也证实了这一点。在压力范围15-25 GPA的扭曲$ 1T $$^{\ prime} $相位中观察到对应于$ re $ $原子振动的拉曼模式的软化。在相同的压力范围内，发现体积的异常变化是由晶格膨胀引起的。体积膨胀与导致八面体失真的层滑动有关，并增加八面体积。相对于15个GPA数据，该样品在25 GPA以上是不可压缩的。在拉曼模式随着压力的转移中也反映了同样的反映。
We report high pressure X-ray diffraction and a detailed systematic Raman measurements on $ReS_2$ sample, which is mechanically exfoliated from a single crystal. A few new Bragg peaks are observed to emerge above 6 GPa indicating a structural transition from distorted $1T$ to distorted $1T$$^{\prime}$ in triclinic structure. The same is corroborated by appearance of new Raman modes in the same pressure range. Softening of the Raman modes corresponding to $Re$ atom vibrations are observed in the distorted $1T$$^{\prime}$ phase in the pressure range 15-25 GPa. In the same pressure range the anomalous change in the volume is found to be induced by the lattice expansion. The volume expansion is related to the sliding of layers leading to octahedral distortion and increase in octahedral volume. The sample is found to be much incompressible above 25 GPa with respect to below 15 GPa data. The same is also reflected in the Raman mode shifts with pressure.
