Final-state interaction in Compton scattering from electron liquids

Sternemann, Christian; Hämäläinen, K.; Kaprolat, A.; Soininen, Aleksi; Döring, G.; Kao, C.‐C.; Manninen, S.; Schülke, W.

doi:10.1103/physrevb.62.r7687

Cited by 28 publications

(30 citation statements)

References 17 publications

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“…A jellium model for including the final state interactions in Compton scattering was proposed by Schülke et al 15 and it could explain most of this additional broadening in the case of lithium. 22 The observed broadening was found to be mostly due to the fact that the final state electron's spectral function has a finite width. In this work we introduce an analytical model for the spectral function, which can be used to analyze the Compton scattering results.…”

Section: Introductionmentioning

confidence: 96%

“…in the Compton scattering spectroscopy, 20 which means that detailed information on the Fermi surface, for example, can be obtained ͑Fermi momenta are of the order of 1 a.u.͒. Recent experiments with this resolution 21,22 have shown, however, that the sharp details in the Compton profiles ͑or in its derivatives͒ have been smeared significantly more than expected on the basis of the experimental resolution. Additionally, the smearing depends on the incident energy, unfortunately in such a way that the effect is larger at lower energies ͑around 10 keV͒ where the highest resolution x-ray spectrometers operate.…”

Section: Introductionmentioning

confidence: 99%

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Final-state electron-electron interaction in Compton scattering

2001

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We introduce an analytic approximation for the spectral function, which describes the final-state electronelectron interaction in the nonresonant inelastic x-ray scattering process. We show that a relatively simple expression is adequate to characterize the excited state. We have evaluated the spectral function for various free electron densities and momentum transfer values and discuss the final state effects in the light of some recent high resolution Compton scattering experiments. It is shown that the observed smearing of the Fermi edge at relatively low incident photon energies can mostly be associated to the final state effects due to the finite width of the spectral function.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Final-state electron-electron interaction in Compton scattering

2001

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“…All three observed features were attributed to correlation effects beyond the RPA [4,[8][9][10][11][12][13]. However, the ion potential was found to cause similar effects [13][14][15][16][17][18].…”

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confidence: 82%

Correlation-Induced Double-Plasmon Excitation in Simple Metals Studied by Inelastic X-Ray Scattering

et al. 2005

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We report a new type of peaklike structure observed in the tail of the dynamic structure factor of simple metals, measured by inelastic x-ray scattering. Based on the momentum-transfer dependence of the energy position and the intensity of this structure, it has been unambiguously attributed to intrinsic plasmonplasmon excitations, an electronic correlation effect that was theoretically predicted by many-body perturbation theory of the homogeneous-electron-gas model beyond the random-phase approximation. This signature appears to be largely unaffected by electron-ion interaction effects. Thus a structure that is primarily caused by correlation effects in the electron gas has been found experimentally in the dynamic structure factor of simple metals. DOI: 10.1103/PhysRevLett.95.157401 PACS numbers: 78.70.Ck, 71.10.Ca, 71.45.2d The appropriate theoretical treatment of correlation in an interacting electron gas at metallic densities still remains a challenge in spite of the large amount of work on this topic. Therefore, experimental methods that can directly test theoretical predictions are very valuable. For systems that closely resemble a homogeneous electron gas (jellium), measurements of the dynamic structure factor S q; ! as a function of the momentum transfer q and the energy loss ! offer such a testing ground of correlation effects, since S q; ! is the Fourier transform in space and time of the density-density correlation function [1]. Inelastic x-ray scattering (IXS) is the favorable experimental method to study S q; ! for large momentum transfers q [2], i.e., when short-range correlations are probed. In particular, the advantage of IXS is the nearly complete absence of multiple scattering in contrast to electron energy-loss spectroscopy (EELS) [3], because in EELS extrinsic multiple excitations can obscure the information on electron correlations. IXS studies on simple metals [4] clearly showed significant deviations of the overall shape of S q; ! for large q from the shape predicted by the jellium model in the random-phase approximation (RPA) [5]. The RPA is known to incorporate long-range correlations only and thus for small q jqj approximately accounts for the energy position and dispersion of collective excitations such as plasmons in simple metals. In both cases the influence of the effective electron-ion interaction is found to be small. For larger q the deviations of the experimental observations from the RPA jellium calculations exhibit three characteristic features: (i) the centroid of S q; ! as a function of ! is shifted to lower energy losses [4]; (ii) a double-peak or a one-peak-one-shoulder structure appears to be universal for all simple metals [5]; (iii) the S q; ! spectra show tails for ! far beyond the upper limit of the jellium (single) particle-hole excitation spectrum [6,7].All three observed features were attributed to correlation effects beyond the RPA [4,[8][9][10][11][12][13]. However, the ion potential was found to cause similar effects [13][14][15][16][17][18]. As a result, it...

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“…Thus, p z -resolutions of about 0.02 a.u. can be achieved [23,24]. A major issue in recent years has become the investigation of nearly free electron (NFE)-metals like Li or Be.…”

Section: Lifetime Effects In Compton Scatteringmentioning

confidence: 99%

“…But about 40 years of intensive investigations of many-body theory -one should not forget that the interacting electron gas is a benchmark in many-body solid state theory -demanded that Z F is about 0.7 ± 0.15 in Li [30]. The solution of this fundamental problem proposed by Sternemann et al [23] was to consider not only lifetime broadening in the initial state -which had been considered up to nowbut also in the final state due to inelastic scattering of the recoiling electron. It is thus assumed that for the measured CP [2,31] J meas (q, ω) ∝ S(q, ω) = Ξ(p, E)…”

Section: Lifetime Effects In Compton Scatteringmentioning

confidence: 99%

Recent Results from (γ, ϱγ) and Compton Spectroscopy

Bell¹

2004

Correlation Spectroscopy of Surfaces, Thin Films, and Nanostructures

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Final-state interaction in Compton scattering from electron liquids

Cited by 28 publications

References 17 publications

Final-state electron-electron interaction in Compton scattering

Final-state electron-electron interaction in Compton scattering

Correlation-Induced Double-Plasmon Excitation in Simple Metals Studied by Inelastic X-Ray Scattering

Recent Results from (γ, ϱγ) and Compton Spectroscopy

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