Electronic structure of the filled tetrahedral compound LiCdP and zinc–blende InP: Application of the interstitial insertion rule

We report on first principles studies of the electronic properties of the filled tetrahedral compound LiCdP and zinc–blende InP, using the full potential linearized augmented plane wave method within the local density approximation. The total energy calculations show that the α phase ( Li + near the anion) to be more stable than the β one ( Li + near the cation) for the LiCdP. The conduction band valleys follow the Γ–L–X ordering of increasing energy for β-LiCdP and InP, and the Γ–X–L one for α–LiCdP. The conduction band modifications are discussed and found to obey the interstitial insertion rule except for the Γ state of β-LiCdP. The valence charge density analysis shows that the Cd–P bond is covalent whereas the Li–P and the Li–Cd ones in α and β phases, respectively, are ionic.