Resonant inelastic soft-x-ray scattering from valence-band excitations in3d0compounds

Abstract

Ti and Mn L ␣,␤ x-ray fluorescence spectra of FeTiO 3 and KMnO 4 were measured with monochromatic photon excitation on selected energies across the L 2,3 absorption edges. The resulting inelastic x-ray-scattering structures and their changes with varying excitation energies are interpreted within the framework of a localized, many-body approach based on the Anderson impurity model, where the radiative process is characterized by transitions to low-energy interionic-charge-transfer excited states. Sweeping the excitation energy through the metal 2p threshold enhances the fluorescence transitions to the antibonding states pushed out of the band of continuous states due to strong metal 3d -ligand 2p hybridization and matching the low-photon-energy satellites in the spectra. Based on the energy position of these charge-transfer satellites with respect to the recombination peak the effective metal 3d -ligand 2p hybridization strength in the ground state of the system can be estimated directly from the experiment. ͓S0163-1829͑97͒04508-6͔

X-ray spectroscopic study of the electronic structure of the high-dielectric-constant materialCaCu3Ti4O12

“…The exact origin of these RIXS features has yet to be determined. Finally, at a zero loss energy, coincident with the excitation energy, is the elastically scattered or recombination peak and it displays significant changes in intensity as the incident photon energy goes in and out of resonance with features in the unoccupied PDOS and in particular is enhanced at both the L 3 21 In their analysis of such scattering in FeTiO 3 it was estimated that the onset of continuum states in FeTiO 3 , above which nonresonant normal fluorescence occurs, is at an energy of about 1 eV above the t 2g peak in the L 3 absorption edge. This estimate is based on the combination of Ti 2p photoemission, valence-band photoemission, and optical spectroscopies, not all of which are currently available for CCTO.…”

Resonant inelastic X-ray scattering as a probe of optical scale excitations in strongly electron-correlated systems: quasi-localized view

“…Various aspects of probing the charge-transfer excitations by this spectroscopy and data interpretation within the Anderson impurity model framework are discussed extensively in the contribution by Kotani [11]. A reader is also referred to publications by present author et al [6,[12][13][14] where the latter issue is addressed.…”

Intermetallic charge transfer inFeTiO3probed by resonant inelastic soft x-ray scattering

“…4͒ spectra. However, the single-cluster calculation yields a theoretical spectrum that is void in this energy region even for FeTiO 3 . Since the single-cluster model failed to reproduce the observed RIXS spectral structure, we have expanded the theoretical concept into a double-cluster ͑including, apart from the Ti with oxygen neighbors, an adjacent Fe ion with respective ligand oxygens͒ model calculation which, as seen below, gives a good account of the experimental results.…”

“…The local symmetry around the transition-metal ions, both Fe and Ti, has D 3d symmetry. In this study, we primarily investigate the characteristics of energy-loss peaks that we experimentally observed at −2.5 and −4.5 eV in the Ti 2p resonant inelastic soft x-ray inelastic scattering ͑RIXS͒ of FeTiO 3 . The interpretation of the data is given using model calculations, which indicate that direct intermetallic charge transfer is present and has similar rates to the more widely accepted cation-anion charge transfer.…”