Raman signatures of inversion symmetry breaking structural transition in quasi-1D compound, (TaSe4)3I.

The breaking of inversion symmetry combined with spin-orbit coupling, can give rise to intrigu- ing quantum phases and collective excitations. Here, we report systematic temperature dependent Raman scattering and theoretical calculations of phonon modes across the inversion symmetry- breaking structural transitions in a quasi-one-dimensional compound (TaSe4)3I. Our investigation revealed the emergence of three additional Raman-active modes in Raman spectra of the low- temperature (LT) non-centrosymmetric (NC) structure of the material.