Evidence of electron–phonon coupling in type-II Weyl semimetal TaIrTe4

Abstract

TaIrTe4, a time-reversal symmetric Weyl semimetal with the allowed minimum Weyl points, has sparked considerable attention and is appealing for a myriad of intriguing physical phenomena, including chiral anomaly, nonlinear Hall effect, dual quantum spin Hall insulator, and superconductivity. However, the electron–phonon coupling central to understanding the fundamental properties remains largely unexplored. In this work, we demonstrate the tell-tale signature of electron–phonon coupling in the type-II Weyl semimetal TaIrTe4 employing temperature-dependent Raman spectroscopy. Our results reveal that the temperature-dependent energy and lifetime of A1 phonon mode at ∼172 cm−1 diverge from the anharmonic model, evidencing the dominated role of phonon–electron rather than phonon–phonon scattering in phonon decay. The theoretically calculated electron–phonon coupling matrix element of the A1 mode is 0.39 eV, indicating substantial coupling to the electronic state. Our findings provide meaningful insights into understanding the fascinating physical properties and quantum phenomena of Weyl semimetal TaIrTe4.