dz2 orbital character of polyhedra in complex solid-state transition-metal compounds

Abstract

In transition-metal compounds, the character of the d orbitals often plays an important role in the development and enhancement of novel physical and chemical properties. Density functional theory calculations of the electronic structures of various d⁰- and d¹-complex transition-metal compounds consisting of either face-sharing octahedra, edge-sharing octahedra, or edge-sharing trigonal prismatic layers were performed to investigate the nature of their d orbitals. The d_z² orbital of the transition metal was shown to make a significant contribution to the electronic structure near the Fermi level in nine different complex transition-metal compounds (oxides, nitrides, and sulfides), regardless of the type of polyhedral geometry and connectivity. The importance of controlling and designing the d_z² orbital character of transition metals near the Fermi level was shown to be important in developing novel physical and chemical properties in complex transition-metal compounds.