论文标题
低频剪切模式的超快动力学以$ \ mathrm {1T'-mote_2} $
Ultrafast dynamics of the low frequency shear mode in $\mathrm{1T'-MoTe_2}$
论文作者
论文摘要
我们使用飞秒泵探针光谱法报告了半学1T'-MOTE2中相干声子的动力学。在室温下的超快子皮秒级时，在0.39 THz处观察到低频和长期剪切声子模式，以前仅在低温TD-Mote2相中以特征性声子的形式报告。与其他光学声子模式不同，发现剪切声子模式与光激发载体强烈搭配。此外，随着激发密度的增加，剪切模式的幅度令人惊讶地降低，这种现象可以归因于激发后晶格温度升高的结果。这些结果提供了有关正常半学1T'和晶状体反转对称性破坏II型WEYL SEMIMITAL TD阶段之间的超快晶格对称性切换的有用物理信息。
We report on the dynamics of coherent phonons in semimetal 1T'-MoTe2 using femtosecond pump-probe spectroscopy. On an ultrafast sub-picosecond time scale at room temperature, a low frequency and long-lifetime shear phonon mode was observed at 0.39 THz, which was previously reported in the form of a characteristic phonon only in the low temperature Td-MoTe2 phase. Unlike the other optical phonon modes, the shear phonon mode was found to strongly couple with photoexcited carriers. Moreover, the amplitude of the shear mode surprisingly decreased with increasing excitation density, a phenomenon which can be attributed to be a consequence of the lattice temperature rising after excitation. These results provide useful physical information on ultrafast lattice symmetry switching between the normal semimetal 1T' and the lattice inversion symmetry breaking Type-II Weyl semimetal Td phases.
