Electronic structure ofRuO2,OsO2, andIrO2

Abstract

The Slater-Koster linear-combination-of-atomic-orbitals (LCAO) interpolation method is applied to fit the results of nonrelativistic augmented-plane-wave (APW) calculations at symmetry points in the Brillouin zone for several metallic transition-metal dioxides with the rutile structure, namely, ${\mathrm{RuO}}_{2}$, ${\mathrm{OsO}}_{2}$, and ${\mathrm{IrO}}_{2}$. This LCAO model, which involves Bloch sums formed from the oxygen $2s\ensuremath{-}2p$ and metal-atom $d$ orbitals, fits 92 APW energy eigenvalues with a 5-mRy rms error by means of 37 adjustable two-center parameters. The results of this APW-LCAO model are applied to determine the band profiles, density of states, and Fermi surfaces for each of these compounds. It is found that the Fermi-surface topology of these materials is altered significantly by the effects of spin-orbit coupling involving the metal-atom $d$ orbitals. These effects are included in this APW-LCAO band model by means of an additional parameter, the spin-orbit parameter ${\ensuremath{\xi}}_{d}$. The resulting Fermi surfaces are in good qualitative agreement with those inferred from magnetothermal-oscillation data by Graebner et al.