标题： 层间剪切声子在过渡金属二硫化物晶格对称性切换中的作用 显示英文标题

标题： Role of interlayer shear phonons on the lattice symmetry switch in a transition-metal dichalcogenide

摘要： 通过使用超短脉冲序列进行相干声子控制，是通过非热途径实现在固体中结构相变的关键。 通过在二维层状材料WTe$_{2}$中的高密度电子激发条件下结合双脉冲激发和时间分辨二次谐波生成技术，我们证明了从Weyl半金属T$_{d}$相到半金属1T$^{\prime}$相的晶格对称性切换与相干层间剪切声子的振幅无关。 这一发现为对称性切换机制提供了新的见解，表明由电子激发驱动的剪切滑动起着主导作用。 显示英文摘要

摘要： Coherent phonon control using ultrashort pulse trains is the key to realizing structural phase transitions in solids by non-thermal pathways. By combining double-pulse excitation and time-resolved second harmonic generation techniques under high-density electronic excitation in a 2D layered material, WTe$_{2}$, we demonstrate that the lattice symmetry switching from the Weyl semimetallic T$_{d}$ to the semimetallic 1T$^{\prime}$ phases is independent of the amplitude of the coherent interlayer shear phonons. This finding provides new insights into the mechanisms for symmetry switching that electronic excitation-driven shear sliding plays a dominant role.