Bonding in skutterudites: Combined experimental and theoretical characterization ofCoSb3

Abstract

We report on the bonding in skutterudites using the ${\mathrm{CoSb}}_3$ example. The theoretical electronic structure is calculated in both density-functional theory and empirical tight-binding frameworks. It is shown to be in good agreement with x-ray photoemission and photoabsorption experiments, and with ${}^{121}\mathrm{Sb}$ Mössbauer spectroscopy. It is then used to demonstrate that (i) the ${\mathrm{Sb}}_4$ rings are not the main structural features to analyze the highest valence-band behavior, (ii) the structure must be described in terms of corner-connected ${\mathrm{CoSb}}_6$ octahedra, which are tilted to form the Sb rings.