| 1. |
- Duda, L.-C., et al.
(författare)
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Resonant inelastic X-ray scattering at the NiO O K-resonance: non-local charge-transfer and double singlet excitations
- 2007
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Ingår i: MAX-lab. - Lund : MAX-lab. ; , s. 270-271
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- NiO is one of the prototypical compounds that has highlighted the importance of correlation effects in transition metal oxides. Core level spectroscopies bear evidence for the highly correlated nature of low energy excitations. For instance, the asymmetry of the Ni2p-line shape has been attributed to non-local charge transfer excitations and multi-site cluster calculations show that solidstate effects generally are appreciable for correlated materials, such as cuprates and high Tc-compounds.....
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| 2. |
- Magnuson, Martin, et al.
(författare)
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Electronic-structure investigation of CeB6 by means of soft-x-ray scattering
- 2001
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 63:7, s. 075101-
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of the heavy fermion compound CeB6 is probed by resonant inelastic soft-x-ray scattering using photon energies across the Ce 3d and 4d absorption edges. The hybridization between the localized 4f orbitals and the delocalized valence-band states is studied by identifying the different spectral contributions from inelastic Raman scattering and normal fluorescence. Pronounced energy-loss structures are observed below the elastic peak at both the 3d and 4d thresholds. The origin and character of the inelastic scattering structures are discussed in terms of charge-transfer excitations in connection to the dipole allowed transitions with 4f character. Calculations within the single-impurity Anderson model with full multiplet effects are found to yield consistent spectral functions to the experimental data.
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| 3. |
- Schmitt, T, et al.
(författare)
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Resonant soft X-ray emission spectroscopy of doped and undoped vanadium oxides
- 2004
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Ingår i: Journal of Alloys and Compounds. - 0925-8388 .- 1873-4669. ; 362:1-2, s. 143-150
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Tidskriftsartikel (refereegranskat)abstract
- Resonant soft X-ray emission (RSXE) spectra of NaV2O5, MoxV1-xO2 and V2O3 have been recorded for a series of excitation energies at resonances of the V L- and O K-absorption band. Resonant excitation allows us, firstly, to separate V 3d and O 2p projected density-of-states of the valence band and, secondly, to study charge-neutral low-energy excitations due to resonant inelastic X-ray scattering (RIXS). We found that both the V L- and the O K-emission spectra clearly show components originating from O 2p- and V 3d-states, reflecting the high degree of hybridization of the valence band in all compounds. At threshold excitation we observed that NaV2O5 spectra are dominated by RIXS whereas MoxV1-xO2 and V2O3 spectra show bandlike features, which may be due to differences in the correlation effects of the compounds. We compared the RSXE spectra with cluster model calculations, which gives a good account for NaV2O5 whereas the RSXE spectra of the other compounds show RIXS only at certain energies well above the threshold. In fact, we interpret the trend in the RSXE spectra of the MoxV1-xO2 compound system as a successive filling of the (rigid) V 3d band with increasing Mo content. (C) 2003 Elsevier B.V. All rights reserved.
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| 4. |
- Butorin, SM, et al.
(författare)
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Resonant valence-to-core x-ray fluorescence spectroscopy on PrO2
- 1997
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Ingår i: JOURNAL OF PHYSICS-CONDENSED MATTER. - : IOP PUBLISHING LTD. - 0953-8984. ; 9:38, s. 8155-8160
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The results of 4f --> 3d x-ray fluorescence measurements, performed with monochromatic-photon excitation at Pr M-4,M-5 absorption edges of PrO2, are presented and discussed in the framework of an Anderson impurity model. The dependence of the fluorescence
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| 5. |
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| 6. |
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| 7. |
- Duda, Laurent, et al.
(författare)
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Resonant Inelastic X-Ray Scattering at the Oxygen K Resonance of NiO: Nonlocal Charge Transfer and Double-Singlet Excitations
- 2006
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 96:067402
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Tidskriftsartikel (refereegranskat)abstract
- We report high-resolution polarization-dependent resonant inelastic x-ray scattering (RIXS) at the O K resonance of NiO showing a rich excitation spectrum. We perform multisite Ni6O19 cluster model calculations, revealing that solid state effects are substantial. We identify a nonlocal charge transfer excitation at 4–5 eV and double-singlet creation at 1.75 eV, both exhibiting significant scattering geometry dependence. Apart from an intense band of local charge transfer excitations (above 5 eV) also dd excitations at 1 eV are observed. Finally, we point out that O K RIXS of correlated metal oxides allows a quantitative and consistent determination of the charge transfer energy and the Hund coupling energy JH.
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| 8. |
- Duda, LC, et al.
(författare)
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Symmetry selection in polarized resonant X-ray emission spectroscopy in La2CuO4
- 1998
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Ingår i: JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN. - : PHYSICAL SOCIETY JAPAN. ; 67:2
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Experimental and theoretical investigations are made for the polarization dependence in the resonant X-ray emission spectra due to the Cu 3d --> 2p electronic transition under the Cu 2p --> 3d resonant excitation (Cu 2p-RXES) in La2CuO4. It is shown that
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| 9. |
- Schmitt, Thorsten, et al.
(författare)
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Electronic structure studies of V6O13 by soft X-ray emission spectroscopy : band-like and excitonic vanadium states
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 69:12, s. 125103-
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Tidskriftsartikel (refereegranskat)abstract
- Resonant soft x-ray emission (SXE) spectra of the mixed valence vanadium oxide V6O13 have been recorded for a series of excitation energies across the V L-absorption band. Resonant excitation allows one to distinguish between charge neutral low-energy excitations and continuum-excited, more band-like V 3d valence band states in the spectra. We find that the V L-emission spectra of V6O13 consist of two distinct components that can be assigned to nearly pure V 3d states, and to V 3dstates that are strongly hybridized with O 2p states, respectively. Band structure calculations of the density functional theory support the assignment of these features. At threshold excitation the V L-emission spectra of V6O13 show strong signatures from excitonic states, the energy dependence of which shows Raman-like behavior. We compare these spectral features in the resonant SXE spectra with cluster model calculations and assign them to dd excitations and charge-transfer excitations, respectively. Finally, we discuss changes in the V L-absorption and emission spectra that take place when changing the sample temperature from 295 K to 120 K. We relate the changes to redistributions in the V 3d partial density of states, which occur at the transition temperature for the metal-semiconductor-transition TMST=150K and find support in our temperature dependent band structure calculations.
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| 10. |
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