“…Recently, superionic Cu 2– x X (X = S, Se) are reported to have ultralow κ and high zT due to the liquid-like behavior of Cu ions around the crystalline sublattice of X and are considered as a new class of phonon–liquid–electron–crystals (PLEC). − ,,− ,,, Further, the superionic CT2 has an interesting structure where the tellurium atom forms a rigid sublattice and the liquid-like Cu ions are distributed randomly in the rigid sublattice and thus classified as PLEC . It has been observed that several state of the art TE materials are tellurides, such as PbTe, SnTe, ,, and Bi 2 Te 3 , , and have better performances than their Se and S counterparts. ,, Thus, the present work focuses on the Raman spectroscopic studies of copper tellurides.…”