Electronic structure and bonding in skutterudite-type phosphides

The electronic structures of the skutterudite-type phosphides ${\mathrm{CoP}}_3$ and ${\mathrm{NiP}}_3$ have been investigated by means of first-principles linear muffin-tin orbital–atomic sphere approximation band-structure calculations. The presence of ${\mathrm{P}}_4$ rings in the skutterudite structure is of great importance in determining the nature of the electronic bands around the Fermi level, composed mainly of π-type molecular orbitals of these units. The metallic character found for ${\mathrm{NiP}}_3$ should be ascribed to the phosphorus framework rather than to the metal atoms. © 1996 The American Physical Society.