Using the crystal parameters in Table , the electronic band structures were obtained using the allelectrons DFT-based augmented spherical method (ASW) and are shown in Fig. . The bands (blue lines) develop along the major directions of the hexagonal Brillouin zones. The zero energy along the vertical axis is considered with respect to E V , at the top of the filled valence band (VB), separated from the empty conduction band (CB) by a band gap. For both phosphides, the zincblende phase has a larger band gap compared to the qtz phase, the smaller magnitude for the latter resulting from the smaller volume per FU leading to increased covalence.