Localized and Delocalized Excitons: Resonant Inelastic X-Ray Scattering in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>La</mml:mi><mml:mrow><mml:mn>2</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Sr</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>NiO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>La</mml:mi><mml:mrow><mml

Collart, Emilie; Shukla, Abhay; Rueff, Jean‐Pascal; Leininger, Ph.; Ishii, Hirofumi; Jarrige, Ignace; Cai, Yong Q.; Cheong, Sang‐Wook; Dhalenne, G.

doi:10.1103/physrevlett.96.157004

Cited by 58 publications

(73 citation statements)

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“…The RIXS ͑or RXES͒ spectra were previously shown to provide detailed information about the bulk electronic properties of various materials, such as the degree of localization, electronic occupancy, and the offsite d-d excitation between separate transition-metal sites. 31,39,42 In this work, we recorded lifetime-broadeningsuppressed x-ray absorption spectra and resonant inelastic x-ray scattering ͑or resonant x-ray emission spectra͒ at the Mn K edge coupled with ab initio electron structure calculations to investigate the intra-and intersite electronic excitations for multiferroic TbMnO 3 crystals.…”

Section: Introductionmentioning

confidence: 99%

Intra- and intersite electronic excitations in multiferroicTbMnO3probed by resonant inelastic x-ray scattering

et al. 2010

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Mn 3d valence states and elementary electronic excitations in single-crystalline TbMnO 3 were probed with resonant inelastic x-ray scattering ͑RIXS͒ ͑or resonant x-ray emission spectroscopy, RXES͒, polarized x-ray absorption spectra and ab initio electron-structure calculations. Polarized Mn K-edge x-ray absorption spectra of TbMnO 3 crystals exhibit a significant anisotropy along three crystallographic directions, particularly for the white-line region. The 1s3p-RXES spectra obtained at the Mn K edge reveal that the quadrupolar Raman regime is restricted predominantly to below the pre-edge peak whereas the fluorescence regime starts from the first pre-edge peak of 1s → 3d transitions, indicating a relatively delocalized character of unoccupied Mn 3d states. The additional K␤ emission profile at energy loss ϳ62 eV is attributed to the off-site dipole Mn 1s-MnЈ 3d and/or Mn 1s-Tb 5d transitions, originating from hybridization between Mn 4p states and neighboring MnЈ 3d / Tb 5d states. The off-site dipole transition makes a considerable contribution to the pre-edge region of Mn K-edge spectrum. Three prominent RIXS features at ϳ2.9, 7, and 11 eV were observed. Based on GGA+ U calculations, the 7 eV region corresponds to transitions from O 2p states to unoccupied minority Mn 3d states, whereas the 11 eV band is ascribed to transitions from the O 2p band to the empty Tb 5d band. The broad 2.9 eV band is attributed to the coexistence of on-site Mn 3d-Mn 3d and off-site Mn 3d-MnЈ 3d transitions.

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Section: Introductionmentioning

confidence: 99%

Intra- and intersite electronic excitations in multiferroicTbMnO3probed by resonant inelastic x-ray scattering

et al. 2010

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“…2,17 For horizontal scattering geometry, with both polarizations within the scattering plane (π polarized), these conditions can only be approached for forward and backward scattering. 20,21 On the other hand, in horizontal-scattering geometry the elastic intensity can be minimized independently of the inelastic intensity. This can be an advantage since it allows the suppression of the elastic 'tail' due to the non-zero energy resolution, leading to a higher signal-to-background ratio.…”

Section: Polarization Dependence Of the Rixs Cross Sectionmentioning

confidence: 99%

Polarization dependence and symmetry analysis in indirectK-edge RIXS

et al. 2010

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We present a study of the charge-transfer excitations in undoped Nd 2 CuO 4 using resonant inelastic X-ray scattering (RIXS) at the Cu K-edge. At the Brillouin zone center, azimuthal scans that rotate the incidentphoton polarization within the CuO 2 planes reveal weak fourfold oscillations. A comparison of spectra taken in different Brillouin zones reveals a spectral weight decrease at high energy loss from forward-to back-scattering. We show that these are scattered-photon polarization effects related to the properties of the observed electronic excitations. Each of the two effects constitutes about 10% of the inelastic signal while the '4p-as-spectator' approximation describes the remaining 80%. Raman selection rules can accurately model our data, and we conclude that the observed polarization-dependent RIXS features correspond to E g and B 1g charge-transfer excitations to non-bonding oxygen 2p bands, above 2.5 eV energy-loss, and to an E g d → d excitation at 1.65 eV.Raman scattering and optical spectroscopy have enabled tremendous contributions to the study of condensed matter systems. Both probes use ∼ 1 eV light and are limited to essentially zero momentum transfer. In order to investigate the charge response of a material throughout the Brillouin zone, photons in the X-ray regime must be used. X-ray Raman scattering, more commonly referred to as resonant inelastic X-ray scattering (RIXS), allows the measurement of the momentum dependence of charge excitations. Even though it has successfully been used to study the physics of a wide array of systems, 1-5 this resonant technique is relatively new and there is still much to learn about the details of its cross section.One of the strengths of conventional Raman scattering derives from the fact that the technique allows the determination of the symmetry of excitations by selecting the polarization of the incident and scattered photons. Only polarization dependent soft (or direct 6 ) X-ray RIXS studies, at the O K-edge or the Cu L-and M-edges of the cuprates, 7-11 have shown that photon polarization can be used to select different electronic excitations. In these cases, the photon polarization effects are understood to come from the direct interaction of the photoelectron, excited into the valence system, with the valence electrons. This is why this type of RIXS is commonly referred to as direct. 6 On the other hand, tuning the incident energy to the Cu K-edge excites the photoelectron into the Cu 4p band approximately 10-20 eV above the 3d valence levels. The relatively large separation in energy from the valence levels as well as the large spatial extent of the 4p orbital are believed to prevent the photoelectron from interacting with the valence system, and this type of RIXS is in turn referred to as indirect. 6 Accordingly, theoretical models of this type of RIXS accordingly do not include possible interactions of the 4p photoelectron with the valence system, 12-15 which is commonly referred to as the '4p-as-spectator' approximation.RIXS investigations of ...

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“…Specifically, RIXS at the Cu K-edge energy has been used extensively to observe excitations in La 2 CuO 4 , [25][26][27][28][29] and the doping dependence has been studied to some degree. 27,30,31 In addition to improvements in instrumentation, recent years have seen advances in understanding of the relation of the RIXS cross-section to the optical loss function and the dynamical structure factor, through both empirical 32 and theoretical means 33 . Theorists have also been engaged in understanding doping-dependent RIXS spectra in terms of electronic band structure, 34,35 although a detailed comparison between theory and experiment has been limited to only a few dopings.…”

Section: 19mentioning

confidence: 99%

Electronic structure of doped lanthanum cuprates studied with resonant inelastic x-ray scattering

et al. 2011

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We report a comprehensive Cu K-edge RIXS investigation of La2−xSrxCuO4 (LSCO) for 0≤x≤0.35, stripe-ordered La1.875Ba0.125CuO4 (LBCO), and La2Cu0.96Ni0.04O4 (LCNO) crystals. The RIXS spectra measured at three high-symmetry momentum transfer (q) positions are compared as a function of doping and for the different dopants. The spectra in the energy range 1-6 eV can be described with three broad peaks, which evolve systematically with increased doping. The most systematic trend was observed for q=(π, 0) corresponding to the zone boundary. As hole doping increased, the spectral weight transfer from high energies to low energies is nearly linear with x at this q. We interpret the peaks as interband transitions in the context of existing band models for this system, assigning them to Zhang-Rice band→upper Hubbard band, lower-lying band→upper Hubbard band, and lower-lying band→Zhang-Rice band transitions. The spectrum of stripe-ordered LBCO was also measured, and found to be identical to the correspondingly doped LSCO, except for a relative enhancement of the near-infrared peak intensity around 1.5-1.7 eV. The temperature dependence of this near-infrared peak in LBCO was more pronounced than for other parts of the spectrum, continuously decreasing in intensity as the temperature was raised from 25 K to 300 K. Finally, we find that 4% Ni substitution in the Cu site has a similar effect on the spectra as does Sr substitution in the La site.

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Localized and Delocalized Excitons: Resonant Inelastic X-Ray Scattering inLa2−xSrxNiO4andLa

Cited by 58 publications

References 20 publications

Intra- and intersite electronic excitations in multiferroicTbMnO3probed by resonant inelastic x-ray scattering

Intra- and intersite electronic excitations in multiferroicTbMnO3probed by resonant inelastic x-ray scattering

Polarization dependence and symmetry analysis in indirectK-edge RIXS

Electronic structure of doped lanthanum cuprates studied with resonant inelastic x-ray scattering

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