Electronic structure of metallicK0.3MoO3and insulating

Abstract

We present high-energy spectroscopy results on the occupied and unoccupied electronic structures of the strongly anisotropic compounds MoO 3 and K 0.3 MoO 3 near the Fermi level. X-ray photoemission reveals a close similarity of the valence-band spectra in both materials. The metal K 0.3 MoO 3 shows an additional Mo 4d-derived conduction band whose population is achieved by electron transfer from K to Mo. This is concluded from studies on intentional surface doping of insulating MoO 3 which leads to the occurrence of Mo 4d-like defect states near the Fermi level. Information on the unoccupied states and their orbital symmetries was obtained by polarization-dependent x-ray absorption spectroscopy. These experiments confirm previous descriptions of the electronic structure in terms of a molecular-orbital picture. For K 0.3 MoO 3 , strong local Mo 4d-O 2p bonding is not only found along the chain direction but also perpendicular to it. This finding is reminiscent of earlier band calculations, which found the chains to form pairs by pronounced transverse hybridization, with the overall bandwidth remaining one dimensionally anisotropic. This adds an important aspect to the discussion on possible Luttinger-liquid physics in the low-dimensional Mo bronzes. ͓S0163-1829͑99͒02636-3͔ PRB 60 M. SING et al.

Electronic structure of the 1D conductor K0.3MoO3studied using resonant inelastic x-ray scattering and soft x-ray emission spectroscopy

“…The XES spectra are recorded for excitation energies well above the O K-edge threshold, and represent the O 2p partial density of states. In both orientations, the width of the emission band is 6 eV, which corresponds well to both XPS measurements, 19,20 and calculations of valence band width. 21 In the E in || [102] orientation, there is an increase in spectral weight,…”

“…This is the energy region near E F , and is dominated by states primarily of Mo 4d character, as previous observed using photoemission spectroscopy. 4,17,20 orbital is parallel to the b axis, and thus the states have the strongest projection along the b axis. 21 With E in || b in our 90< measurement geometry, we only detect emission which has a polarization vector perpendicular to b, and thus dipole emission from these states is most easily observed with E in || [102].…”

X-ray absorption and magnetic circular dichroism characterization of Mo1–xFexO2 (x = 0–0.05) thin films grown by pulsed laser ablation

“…2 displays the Mo M 3,2 -edge (3p→4d) NEXAFS spectra of Mo 1−x Fe x O 2 thin films in TEY mode collected at RT. The spectra are dominated by large 3p core-hole spin-orbit coupling energy, which divides them roughly into the M 3 (3p 3/2 ) and M 2 (3p 1/2 ) regions at low and high photon energy, respectively [14]. The spectral line shape at Mo M 3 -edge of the undoped MoO 2 is different from that of Fe-doped thin films.…”

Formation of one-dimensional molybdenum oxide on Mo(112)

“…Nevertheless, the O 1s signal was used to calibrate the amount of oxygen on the (2x3) surface by comparison with the spectra of an ultra-thin silica film grown on the same Mo(112) substrate, for which the atomic structure has recently been determined [37,38] [42]. In the case of ultra-thin oxide films, additional screening by a m etal substrate underneath the film may result in lowering of the measured BE values.…”