We present an exploration of the effect of electron-phonon coupling and broken inversion symmetry on the electronic and thermal properties of the semimetal LaRhGe₃. Our transport measurements reveal evidence for electron-hole compensation at low temperatures, resulting in a large magnetoresistance of 3000% at 1.8 K and 14 T. The carrier concentration is on the order of 10²¹/cm³ with high carrier mobilities of 2000 cm²/Vs. When coupled to our theoretical demonstration of symmetry-protected almost movable Weyl nodal lines, we conclude that LaRhGe₃ supports a Weyl semimetallic state. We discover superconductivity in this compound with a T_c of 0.39(1) K and B_c(0) of 2.2(1) mT, with evidence from specific heat and transverse-field muon spin relaxation. We find an exponential dependence in the normal state electrical resistivity below ~50 K, while Seebeck coefficient and thermal conductivity measurements each reveal a prominent peak at low temperatures, indicative of strong electron-phonon interactions. To this end, we examine the temperature-dependent Raman spectra of LaRhGe₃ and find that the lifetime of the lowest energy A₁ phonon is dominated by phonon-electron scattering instead of anharmonic decay. We conclude that LaRhGe₃ has strong electron-phonon coupling in the normal state, while the superconductivity emerges from weak electron-phonon coupling. These results open up the investigation of electron-phonon interactions in the normal state of superconducting non-centrosymmetric Weyl semimetals.

我们探索了电子-声子耦合和打破反转对称性对半金属 LaRhGe₃ 的电子和热性能的影响。我们的输运测量揭示了低温下电子空穴补偿的证据，导致在 1.8 K 和 14 T 下具有 3000% 的大磁阻。载流子浓度约为 10²¹/cm³，载流子迁移率高达 2000 cm²/Vs。当与我们对对称性保护的几乎可移动的 Weyl 节点线的理论演示相结合时，我们得出结论，LaRhGe₃ 支持 Weyl 半金属态。我们在这种化合物中发现了超导性，T_c 为 0.39（1） K，B _c（0） 为 2.2（1） mT，比热和横向场 μ 子自旋弛豫的证据。我们发现，低于 ~50 K 的常态电阻率呈指数依赖性，而塞贝克系数和热导率测量值在低温下都显示一个明显的峰值，表明电子-声子相互作用很强。为此，我们研究了 LaRhGe₃ 的温度依赖性拉曼光谱，发现最低能量的 A₁ 声子的寿命以声子电子散射为主，而不是非谐波衰变。我们得出结论，LaRhGe₃ 在正常状态下具有很强的电子-声子耦合，而超导性来自弱电子-声子耦合。这些结果开启了对超导非中心对称 Weyl 半金属正常状态下电子-声子相互作用的研究。