We present a study based on first-principles calculations of the vibrational and spectroscopic properties of four types of layered boron nitride (BN) polymorphs:
e-BN (AA),
h-BN (
),
r-BN (ABC), and
b-BN (AB). By using density functional perturbation theory with van der Waals corrections, we calculate phonon frequencies and Raman/infrared (IR) activities at the
point and extract specific spectral fingerprints for each stack. In
e-BN, we observe a sharp, isolated high-frequency
mode at
that is active in both Raman and IR. For
h-BN, the characteristic Raman
line occurs at
. The out-of-plane IR-active
branch shows a mid-frequency TO/LO pair at 673.5/
, which closely matches experimental results. Rhombohedral
r-BN has a strong, coincident Raman/IR high-frequency feature (
E) at
, along with a large IR LO partner at
, consistent with observed Raman and IR signatures. Bernal
b-BN displays the most complicated pattern. It combines a robust mid-frequency
pair (TO/LO at 697.9/
) with multiple high-frequency
modes (TO near 1416.9 and
, each with LO counterparts). These stack-dependent Raman and IR fingerprints match existing experimental data for
h-BN and
r-BN and provide clear predictions for
e-BN and
b-BN. The results offer a consistent framework for identifying and interpreting vibrational spectra in layered
boron nitride and related materials.
Full article
