Electronic Structure and Stability of Spinel Oxides

Abstract

Using first-principles band structure method, we have calculated the total energies, the structural parameters, and the band gaps of the closed-shell A I I B 2 I I I O 4 and A I V B 2 I I O 4 spinel oxides in both normal and inverse spinel structures. We find that a correct description of the internal atomic relaxation is crucial to predict the stability of the spinels. The preference of cations with delocalized valence d states (e.g., Zn) to form covalent tetrahedral bonds also plays a significant role in determining the cation distribution in the spinels. Furthermore, we find that the band structures of these spinel compounds depend strongly on the cation distribution. For most of the spinels studied here, the calculated band gaps for the inverse spinels are smaller than the corresponding normal spinels.