Evidence for dominant phonon-electron scattering in Weyl semimetal WP$_{2}$

Abstract

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 these behaviors remain largely unexplored. Here we reveal signatures of significant phonon-electron scattering in the type-II Weyl semimetal 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 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.

Optical response from charge-density waves in Weyl semimetals

“…Until recently, this work on CDW transport was focused on quasi-1D systems, where the single-particle gap could be viewed as originating from nesting of a single-band Fermi surface. However, the discovery of Weyl semimetals [28][29][30][31][32][33][34][35] and their anomalous transport properties [36][37][38][39][40][41][42][43][44] has sparked interest in the phenomena that emerges when the CDW order opens a gap between Weyl fermions of opposite chirality [38,[45][46][47][48][49][50][51]. Theoretically, it has been shown that for a magnetic Weyl-CDW, the CDW phase couples to the electromagnetic field as a dynamical electromagnetic theta angle.…”

Topological Quantum Materials from the Viewpoint of Chemistry

“…Some recent Raman spectroscopic studies further signify the importance of electronphonon scattering among microscopic scattering processes on the transport properties of Weyl semimetals. 223,224 Since, electronelectron interaction is not a dominating factor for most of the topological semimetals, understanding the electron-phonon interaction is essential to explore hydrodynamic effects in this broad class of materials.…”

Optical Response from Charge-Density Waves in Weyl Semimetals

“…Until recently, this work on CDW transport was focused on quasi-1D systems, where the single-particle gap could be viewed as originating from nesting of a single-band Fermi surface. However, the discovery of Weyl semimetals [28][29][30][31][32][33][34][35][36] and their anomalous transport properties [37][38][39][40][41][42][43][44][45] has sparked interest in the phenomena that emerges when the CDW order opens a gap between Weyl fermions of opposite chirality [39,[46][47][48][49][50][51][52]. Theoretically, it has been shown that for a magnetic Weyl-CDW, the CDW phase couples to the electromagnetic field as a dynamical electromagnetic theta angle.…”