Electronic structure and bonding in skutterudite-type phosphides

The electronic structures of the skutterudite-type phosphides CoP₃ and NiP₃ have been investigated by means of first-principles linear muffin-tin orbital--atomic sphere approximation band-structure calculations. The presence of P₄ 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 NiP₃ should be ascribed to the phosphorus framework rather than to the metal atoms. {} 1996 The American Physical Society.