Phonon dispersion of (a) TaX (X = N, P, As, Sb) and (b) ZrY (Y = Se, Te) binaries calculated using the density functional perturbation theory (DFPT) for supercell of size 2 × 2 × 2 . The mass difference Δ m is provided in units of g/mol. A prototype crystal structure of TaSb is given in the inset. The primitive unit cell contains one Ta and one X (Sb) atom at (2/3, 0.0, 2/3) and (0.0, 1/2, 0.0) sites, respectively. TDP is marked in the phonon spectrum of TaSb and ZrSe along the Γ–A path. (c) An enlarged view of phonon dispersion in TaSb along Γ–A path. Colors and numbers depict distinct phonon modes. Arabic (Roman) numerals are used to mark phonon modes before (after) the band-inversion. Some data from Ref. [42] have been reused to produce this figure.