Mode-resolved reciprocal space mapping of electron-phonon interaction in the Weyl semimetal candidate Td-WTe2
Mode-resolved reciprocal space mapping of electron-phonon interaction in the Weyl semimetal candidate Td-WTe2
复制标题
外尔半金属候选 Td-WTe2 中电子-声子相互作用的模式解析倒易空间映射
DOI：
10.1038/s41467-020-16076-0
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发表时间：
2020-05-26
影响因子：
16.6
通讯作者：
Bauer, Michael
中科院分区：
文献类型：
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作者：
Hein, Petra;Jauernik, Stephan;Bauer, Michael
相干声子的激发为在超快时间尺度上控制量子材料的基本性质提供了独特的能力。最近，有人预测，在过渡金属二硫化物Td-WTe2中，拓扑保护的Weyl半金属相可以被控制，并最终在层间剪切模式的相干激发下被破坏。通过以飞秒分辨率监测电子结构的变化，我们提供了直接的实验证据，证明剪切模式作用于定义相位的Weyl点附近的电子态。此外，我们观察到带自旋分裂的周期性减少，这是WTe2的Weyl相稳定非中心对称Td基态的明显电子特征。通过与高频相干声子模式的比较，最终证明了所观察到的电子结构变化具有剪切模式选择性。我们的实时观察揭示了对电子过程的直接实验见解，这些过程对Td-WTe2中相干声子诱导的拓扑相变至关重要。
The excitation of coherent phonons provides unique capabilities to control fundamental properties of quantum materials on ultrafast time scales. Recently, it was predicted that a topologically protected Weyl semimetal phase in the transition metal dichalcogenide Td-WTe2 can be controlled and, ultimately, be destroyed upon the coherent excitation of an interlayer shear mode. By monitoring electronic structure changes with femtosecond resolution, we provide here direct experimental evidence that the shear mode acts on the electronic states near the phase-defining Weyl points. Furthermore, we observe a periodic reduction in the spin splitting of bands, a distinct electronic signature of the Weyl phase-stabilizing non-centrosymmetric Td ground state of WTe2. The comparison with higher-frequency coherent phonon modes finally proves the shear mode-selectivity of the observed changes in the electronic structure. Our real-time observations reveal direct experimental insights into electronic processes that are of vital importance for a coherent phonon-induced topological phase transition in Td-WTe2.