Raman scattering investigation of quasi-one-dimensional superconductor Ta$_{4}$Pd$_{3}$Te$_{16}$

TL;DR

This study uses polarized Raman scattering to analyze phonon modes in the superconductor Ta$_{4}$Pd$_{3}$Te$_{16}$, revealing potential charge-density-wave fluctuations and providing insights into its lattice dynamics.

Contribution

First-principles calculations combined with Raman measurements identify phonon modes and suggest charge-density-wave phenomena in Ta$_{4}$Pd$_{3}$Te$_{16}$.

Findings

28 Raman active modes observed

Phonon linewidth of A$_{g}$ mode increases with decreasing temperature

Possible charge-density-wave fluctuations below 140-200 K

Abstract

We have performed polarized Raman scattering measurements on the newly discovered superconductor Ta$_{4}$Pd$_{3}$Te$_{16}$ ($T_c = 4.6$ K). We observe twenty-eight out of thirty-three Raman active modes, with frequencies in good accordance with first-principles calculations. Although most of the phonons observed vary only slightly with temperature and do not exhibit any asymmetric profile that would suggest strong electron-phonon coupling, the linewidth of the A$_{g}$ phonon mode at 89.9 cm$^{-1}$ shows an unconventional increase with temperature decreasing, which is possibly due to a charge-density-wave transition or the emergence of charge-density-wave fluctuations below a temperature estimated to fall in the 140-200 K range.