Raman spectra will be an “image” of the density of vibrational states (DVS) [24]. The Raman spectrum of ZrN, as expected, isdominated by an asymmetric band centred at around 500 cm−1 , and in the low frequency region by the presence of two bands
centred at around 165 and 220 cm−1 , reflecting the material's DVS.
In the low frequency range, the bands are attributed to the
disorder of single phonons and second order processes. For
higher frequencies the presence, and the asymmetry, of the
bands is due to the superposed contributions of disorder of
optical phonons and second order combination of acoustic and
optical processes [25].