The band structures are mirrored by the site projected densities of states (DOS) shown in the right part of Fig. . As a general feature, the P(DOS) show higher intensity than the B(DOS) and Al(DOS) due to the lower electronegativities of boron and aluminum compared to phosphorus, as discussed above. The Fermi level is represented by a vertical line at 0 along the horizontal energy axis, while the vertical axis corresponds to the DOS expressed in eV -1 units, translating the number of states per unit energy. The valence band (VB) is wider in BP than in AlP with the characteristics of a small separation between s-prevailing states from -16 to -10 eV and the p-prevailing states from -9 eV up to E V (top of the VB) in BP, and a larger separation for s-states from -12 to -9 eV and p-states from -6 up to E V in AlP. Such a feature can be related to the larger interatomic distances in AlP vs. BP.