Momentum-Dependent Charge Transfer Excitations in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Cu<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:ma

Wang, Yunyu; Zhang, Fuchun; Dravid, V. P.; Ng, Kwai-Kong; Klein, Miles V.; Schnatterly, S. E.; Miller, L. L.

doi:10.1103/physrevlett.77.1809

Cited by 64 publications

(48 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…18,19,20,21,22 The motion of a single particle is hindered by the interaction of its spin with the AF background. This can be described in terms of a spin polaron.…”

Section: B Hubbard Exciton and Orbital Ordermentioning

confidence: 99%

Mott-Hubbard exciton in the optical conductivity ofYTiO3andSmTiO3

et al. 2008

View full text Add to dashboard Cite

In the Mott-Hubbard insulators YTiO3 and SmTiO3 we study optical excitations from the lower to the upper Hubbard band,The multi-peak structure observed in the optical conductivity reflects the multiplet structure of the upper Hubbard band in a multi-orbital system. Absorption bands at 2.55 and 4.15 eV in the ferromagnet YTiO3 correspond to final states with a triplet d 2 configuration, whereas a peak at 3.7 eV in the antiferromagnet SmTiO3 is attributed to a singlet d 2 final state. A strongly temperature-dependent peak at 1.95 eV in YTiO3 and 1.8 eV in SmTiO3 is interpreted in terms of a Hubbard exciton, i.e., a charge-neutral (quasi-)bound state of a hole in the lower Hubbard band and a double occupancy in the upper one. The binding to such a Hubbard exciton may arise both due to Coulomb attraction between nearest-neighbor sites and due to a lowering of the kinetic energy in a system with magnetic and/or orbital correlations. Furthermore, we observe anomalies of the spectral weight in the vicinity of the magnetic ordering transitions, both in YTiO3 and SmTiO3. In the G-type antiferromagnet SmTiO3, the sign of the change of the spectral weight at TN depends on the polarization. This demonstrates that the temperature dependence of the spectral weight is not dominated by the spin-spin correlations, but rather reflects small changes of the orbital occupation.

show abstract

“…18,19,20,21,22 The motion of a single particle is hindered by the interaction of its spin with the AF background. This can be described in terms of a spin polaron.…”

Section: B Hubbard Exciton and Orbital Ordermentioning

confidence: 99%

Mott-Hubbard exciton in the optical conductivity ofYTiO3andSmTiO3

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Notably, our calculations assume purely in-plane excitations (q z = 0). [17] We consider next the more challenging case of insulating SCOC, where a magnetic gap is present and it has not been clear how the EELS spectra [7] are related to the plasmon excitation. As in the metallic case, the starting point is the dispersion of Eq.…”

mentioning

confidence: 99%

“…[19] Taking ω 0 =2 eV and the same γ as in Eq. 2, the EELS data [7] on SCOC can be fitted to Eq. 4 with ω p = 1.3eV [1 + 3S xy ].…”

mentioning

confidence: 99%

Dispersion anomalies induced by the low-energy plasmon in the cuprates

Markiewicz

Bansil

2007

Phys. Rev. B

View full text Add to dashboard Cite

We discuss the characteristic effects of the electron plasmon interaction resulting from the ∼ 1 eV plasmon, which is a universal feature in the cuprates. Using the framework of a one-band tight binding model, we identify signatures of this low energy plasmon in the electronic structure of metallic overdoped Bi2212 as well as half-filled insulating SCOC. The electron-plasmon interaction is found to yield renormalizations near the Fermi energy in reasonable accord with experimental observations, and to produce dispersion anomalies at higher energies.PACS numbers: 71.38.Cn, 71.45.Gm Quasiparticle dispersions near the Fermi energy in the cuprates are renormalized (reduced) by a factor of Z ∼ 0.3 − 0.6[1] in comparison to the band theory predictions based on the conventional LDA picture, interrupted by the appearance of low energy 'kinks' or dispersion anomalies in the 50-70 meV energy range, which arise from the coupling of the electronic system with phonons[2] and/or magnetic modes [3]. Interestingly, the 'spaghetti' of various hybridized and unhybridized Cu and O bands starting around 1 eV in the cuprates seems to remain more or less unrenormalized. [4] Recalling that optical [5] and electron energy loss spectroscopy (EELS) experiments [6,7] have shown the presence of dispersive plasmons in the cuprates lying at ∼1 eV, we explore the effects of such a low energy plasmon in this Letter. The plasmon is found to induce renormalizations in the low energy regime in both the metallic and the insulating cuprates, which are in substantial accord with the corresponding experimental results. We emphasize that plasmons in 3D materials typically lie at ∼10 eV and therefore have little influence on the electronic states in the 0-1 eV range.We approach the problem within the framework of a one-band tight-binding model and consider the limiting cases of a metal with the example of overdoped Bi 2 Sr 2 CaCu 2 O 8 (Bi2212) [8,9] and the insulator with the example of half-filled Sr 2 CuO 2 Cl 2 (SCOC) [10]. The dielectric functions computed via the random phase approximation (RPA) yield loss functions and the associated plasmon dispersions in both Bi2212 and SCOC, which are in reasonable accord with the corresponding EELS data. The generic effects of the electron-plasmon interaction on the electronic structure and how the low energy plasmon in the metal and the insulator induces characteristic dispersion anomalies and renormalizations of the spectrum are then delineated via a first order calculation of the electronic self energy.We discuss first the metallic case of overdoped Bi2212. Here the magnetic gap has collapsed fully and we take the bare electronic dispersion to be given by a one-band tight-binding model fitted to the LDA-based band structure of Bi2212 in the vicinity of the Fermi energy (E F ) as follows[1]:where c α (na) = cos(nk α a) for α = x or y, n is an integer, and a is the in-plane lattice constant. Hopping parameters appropriate for Bi2212 (neglecting bilayer splitting) [1] are: t=360 meV, t ′ = −100 meV, t ′′...

show abstract

“…2 Recently, taking advantage of strong synchrotron sources, the resonant inelastic x-ray scattering (RIXS) has become a powerful tool to probe charge excitations in solids. 3,4,5,6,7,8,9 In transition-metal compounds, K-edge resonances are widely used to observe momentum dependence, because corresponding x-rays have wavelengths the same order of lattice spacing.…”

Section: Introductionmentioning

confidence: 99%

Analysis of resonant inelastic x-ray scattering at theKedge in NiO

2007

View full text Add to dashboard Cite

We analyze the resonant inelastic x-ray scattering (RIXS) spectra at the Ni K edge in an antiferromagnetic insulator NiO by applying the theory developed by the present authors. It is based on the Keldysh Green's function formalism, and treats the core-hole potential in the intermediate state within the Born approximation. We calculate the single-particle energy bands within the Hartree-Fock approximation on the basis of the multi-orbital tight-binding model. Using these energy bands together with the 4p density of states from an ab initio band structure calculation, we calculate the RIXS intensities as a function of energy loss. By taking account of electron correlation within the random phase approximation (RPA), we obtain quantitative agreement with the experimental RIXS spectra, which consist of prominent two peaks around 5 eV and 8 eV, and the former shows considerable dispersion while the latter shows no dispersion. We interpret the peaks as a result of a band-to-band transition augmented by the RPA correlation.

show abstract

Momentum-Dependent Charge Transfer Excitations inSr2CuO2

Cited by 64 publications

References 17 publications

Mott-Hubbard exciton in the optical conductivity ofYTiO3andSmTiO3

Mott-Hubbard exciton in the optical conductivity ofYTiO3andSmTiO3

Dispersion anomalies induced by the low-energy plasmon in the cuprates

Analysis of resonant inelastic x-ray scattering at theKedge in NiO

Contact Info

Product

Resources

About