Observation of low-frequency Raman peak in layered WTe$_2$

TL;DR

This study reports the discovery of a new low-frequency Raman peak in bulk WTe$_2$, providing insights into its vibrational modes and potential implications for layered ferroelectric materials.

Contribution

The paper identifies a previously unreported Raman peak at 9 cm$^{-1}$ in WTe$_2$ and confirms its symmetry and theoretical consistency, advancing understanding of low-frequency vibrational modes.

Findings

Discovery of a new Raman peak at 9 cm$^{-1}$

The novel peak has $A_1$ symmetry

Results align with first principles calculations

Abstract

WTe$_2$ recently attracted considerable attention as a layered material exhibiting ferroelectricity, giant magnetoresistance, and pressure-induced superconductivity. In this study, we performed Raman spectroscopy on bulk WTe$_2$, including the unreported low frequency region. A novel Raman peak (P0) was found at approximately 9 cm$^{-1}$ in addition to the seven already known peaks. Furthermore, the angular and polarization dependence of the spectra revealed that the novel peak had $A_1$ symmetry. The existence of this novel peak is consistent with first principles calculations by another group. Our work paves the way for studying the low frequency vibration modes of atomic layer ferrolectric films.