Figure 4.

Phonon bandstructure and phonon DOS of the $\epsilon$-Al₃Nb (a), $\sigma$-AlNb₂ (b), and $\delta$-AlNb₃ phase (c) at 0 K. The paths in the first Brilloiun zone were chosen based on the crystal symmetry considerations, as proposed by Setyawan and Curtarolo [34]. (d) Phonon bandstructure of $\delta$-AlNb₃ at elevated temperatures.