Topological semimetals have revealed a wide array of novel transport phenomena, including electron hydrodynamics, quantum field theoretic anomalies, and extreme magnetoresistances and mobilities. However, the scattering mechanisms central to the fundamental transport properties remain largely unexplored. Here, we reveal signatures of significant phonon-electron scattering in the type-II Weyl semimetal ${\mathrm{WP}}_2$ via temperature-dependent Raman spectroscopy. Over a large temperature range, we find that the decay rates of the lowest energy $A_1$ modes are dominated by phonon-electron rather than phonon-phonon scattering. In conjunction with first-principles calculations, a combined analysis of the momentum, energy, and symmetry-allowed decay paths indicates this results from finite momentum interband and intraband scattering of the electrons. The excellent agreement with theory further suggests that such results could be true for the acoustic modes. We thus provide evidence for the importance of phonons in the transport properties of topological semimetals and identify specific properties that may contribute to such behavior in other materials.

中文翻译：

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Weyl SemimetalWP2中主要声子-电子散射的证据

拓扑半金属已经揭示了各种各样的新颖的传输现象，包括电子流体动力学，量子场理论异常以及极端的磁阻和迁移率。然而，对于基本传输性质至关重要的散射机制仍未得到充分研究。在这里，我们揭示了II型Weyl半金属中明显的声子-电子散射的特征${\mathrm{可湿性粉剂}}_2$通过依赖温度的拉曼光谱。在较大的温度范围内，我们发现最低能量的衰减率${\mathrm{一种}}_{\mathrm{1个}}$模由声子-电子而不是声子-声子散射控制。结合第一性原理计算，对动量，能量和对称性允许的衰减路径的综合分析表明，这是由于电子有限的带间和带内散射造成的。与理论的极好的一致性进一步表明，这种结果对于声模可能是正确的。因此，我们提供了声子在拓扑半金属的传输特性中的重要性的证据，并确定了可能有助于其他材料中这种行为的特定特性。