Fermi surface ofMoO2studied by angle-resolved photoemission spectroscopy, de Haas–van Alphen measurements, and electronic structure calculations

Abstract

A comprehensive study of the electronic properties of monoclinic MoO 2 from both an experimental and a theoretical point of view is presented. We focus on the investigation of the Fermi body and the band structure using angle-resolved photoemission spectroscopy, de Haas-van Alphen measurements, and electronic structure calculations. For the latter, the full-potential augmented spherical wave method has been applied. Very good agreement between the experimental and theoretical results is found. In particular, all Fermi surface sheets are correctly identified by all three approaches. Previous controversies concerning additional holelike surfaces centered around the Z and B points could be resolved; these surfaces were artifacts of the atomic-sphere approximation used in the old calculations. Our results underline the importance of electronic structure calculations for the understanding of MoO 2 and the neighboring rutile-type early transition-metal dioxides. This includes the low-temperature insulating phases of VO 2 and NbO 2 , which have crystal structures very similar to that of molybdenum dioxide and display the well-known prominent metal-insulator transitions.

Unconventional metallic behavior and superconductivity in the K-Mo-O system

“…Structural and electronic properties of this dioxide remain under investigation. 34,37 For the K x MoO 2−␦ compound, simulations of x-ray powder diffractograms suggest that potassium atoms occupy interstitial positions of the oxygen deficient MoO 2 as indicated on the right panel of the Fig. 3.…”

“…[34][35][36] Due to those Mo-Mo bonds and other structural aspects, MoO 2 is supposed to show anisotropic behavior. Structural and electronic properties of this dioxide remain under investigation.…”

Epitaxial growth and metallicity of rutile MoO2thin film

“…The lowest peak α extends to the low energy region; in Figure 4-(b) its tail appears as the Lorentz mode. 22,27,46 This mode has a larger value for the peak width when compared to the other modes, and its strength is the lowest. 27,46 The β near 3.32 eV shows a similar energy with the absorption edge of e g band from previous works.…”

“…This diagram is based on the band structure and the density of states of previously reported literatures. 27,46 Note that Mo +4 has an electron configuration of [Kr] 4d 2 . The d orbital can be separated into two sub-bands, i.e., t 2g and e g bands by the crystal field.…”

“…The t 2g band has a lower energy level and is partially filled by the two electrons, and the e g band is empty and has a higher energy level located above the Fermi energy. 27,46 The imaginary part (k) of the refraction index is related to the real part (σ 1 ) of the optical conductivity. In Figure 5, there are three distinct absorption peaks in the optical conductivity: the lowest peak denoted as α at 1.17 eV, another one (β) at 3.32 eV, and the highest one (γ) which has a double peak feature around 4~5 eV.…”