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

TL;DR

This study demonstrates that phonon-electron scattering dominates over phonon-phonon interactions in WP$_{2}$, a Weyl semimetal, influencing its transport properties and highlighting the significant role of phonons in topological semimetals.

Contribution

It provides experimental and theoretical evidence of dominant phonon-electron scattering in WP$_{2}$, a topological semimetal, revealing a key mechanism affecting its transport behavior.

Findings

Phonon-electron scattering dominates decay rates of $A_{1}$ modes.

First-principles calculations confirm intraband electron scattering.

Results suggest similar behavior may occur in acoustic modes.

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.