Raman scattering investigation of the quasi-one-dimensional superconductor Ta₄Pd₃Te₁₆

We have performed polarized Raman scattering measurements on the newly discovered superconductor Ta₄Pd₃Te₁₆ ($T_{\text{c}}=4.6$ K). We observe 28 out of 33 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. (paper)