Three-body scattering theory of correlated hole and electron states

Calandra, C.; Manghi, F.

doi:10.1103/physrevb.50.2061

Cited by 39 publications

(28 citation statements)

References 2 publications

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“…A detailed comparison between theory and experiment is shown in Figure 6. Figure 7 shows the experimentally extracted imaginary part of the self energy in direct comparison with results based on the DMFT (using a pertrubative FLEX-solver) and an alternative many-body technique, the so called three body scattering (3BS) scheme [81]. A reasonable agreement with the spin-integrated as well as spin-resolved experimental data for all three surfaces and various photon-energies has been achieved.…”

Section: Photoemission Spectroscopysupporting

confidence: 59%

A self-consistent, relativistic implementation of the LSDA+DMFT method

Minář

Ebert²,

Chioncel

2017

Eur. Phys. J. Spec. Top.

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Abstract. In this review we report on developments and various applications of the combined Density Functional and Dynamical Mean-Field Theory, the so-called LSDA + DMFT method, as implemented within the fully relativistic KKR (Korringa-Kohn-Rostoker) band structure method. The KKR uses a description of the electronic structure in terms of the single-particle Green function, which allows to study correlation effects in ordered and disordered systems independently of its dimensionality (bulk, surfaces and nano-structures). We present self-consistent LSDA+DMFT results for the ground state and spectroscopic properties of transition metal elements and their compounds. In particular we discuss the spin-orbit induced orbital magnetic moments for Fe xNi1−x disordered alloys, the magnetic Compton profiles of fcc Ni and the angle-resolved photoemission spectroscopy (ARPES) spectra for gallium manganese arsenide dilute magnetic semiconductors. For the (GaMn)As system a direct comparison with the experimental ARPES spectra demonstrates the importance of matrix element effects, the presence of the semi-infinite surface and the inclusion of layer-dependent self-energies.

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Section: Photoemission Spectroscopysupporting

confidence: 59%

A self-consistent, relativistic implementation of the LSDA+DMFT method

Minář

Ebert²,

Chioncel

2017

Eur. Phys. J. Spec. Top.

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“…60 The corresponding self-energy DMFT (E) is calculated fully self-consistently (e.g., in charge and selfenergy) from the DMFT. 17,61 Additionally we accounted for correlation effects within the 3BS approximation, 20 where the self-energy is calculated using a configuration interactionlike expansion. Due to the explicit consideration of hole and three-particle configurations this method allows for a detailed analysis of lifetime effects caused by electron-hole pair decays.…”

Section: Theorymentioning

confidence: 99%

“…More recently, theories beyond DFT have been developed to take many-body interaction (i.e., correlation effects) in a more quantitative way into account. In this context we mention the dynamical mean-field theory (DMFT) [17][18][19] which replaces the problem of describing correlation effects in a periodic lattice by a correlated impurity coupled to a self-consistent bath and an alternative approach, the three-body scattering (3BS) approximation 20 which takes into account the relaxation of a hole by an Auger-like excitation in the valence band, formed by one hole plus an electron-hole excitation using a T-matrix formalism. Both theories allow calculating an approximated momentum and energy-dependent spectral function which is described by the bare-particle band structure and the complex self-energy function .…”

Section: Introductionmentioning

confidence: 99%

Effects of spin-dependent quasiparticle renormalization in Fe, Co, and Ni photoemission spectra:An experimental and theoretical study

Sánchez-Barriga

Braun²,

Minář³

et al. 2012

Phys. Rev. B

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We have investigated the spin-dependent quasiparticle lifetimes and the strength of electron correlation effects in the ferromagnetic 3d transition metals Fe, Co, and Ni by means of spin-and angle-resolved photoemission spectroscopy. The experimental data are accompanied by state-of-the-art many-body calculations within the dynamical mean-field theory and the three-body scattering approximation, including fully relativistic calculations of the photoemission process within the one-step model. Our quantitative analysis reveals that inclusion of local many-body Coulomb interactions are of ultimate importance for a realistic description of correlation effects in ferromagnetic 3d transition metals. However, we found that more sophisticated many-body calculations with larger modifications in the case of Fe and Co are still needed to improve the quantitative agreement between experiment and theory. In general, it turned out that not only the dispersion behavior of energetic structures should be affected by nonlocal correlations but also the line widths of most of the photoemission peaks are underestimated by the current theoretical approaches. The increasing values of the on-site Coulomb interaction parameter U and the band narrowing of majority spin states obtained when moving from Fe to Ni indicate that the effect of nonlocal correlations becomes weaker with increasing atomic number, whereas correlation effects tend to be stronger.

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“…6 On the theoretical side we have calculated spectral functions and quasiparticle energies by solving a multiorbital Hubbard Hamiltonian according to the three-body scattering ͑3BS͒ method. [7][8][9][10][11] This approach can be seen as an extension to the solid state of the configuration-interaction scheme used for finite systems: the Hubbard Hamiltonian is projected on a set of states obtained by adding a finite number of electron-hole pairs to the ground state of the single-particle Hamiltonian and this expansion is truncated to include one electron-hole pair; this approximation is particularly justified for systems with a large band occupation since the role of extra configurations depends on the overall number of empty states necessary for the addition of electron-hole pairs.The effect of electron correlation on one-electron removal energies from a partially filled band is described in terms of interactions between three-body configurations ͑one hole plus one electron-hole pair͒ giving rise to hole-hole and holeelectron scattering; the efficiency of these scattering processes depends first of all on the strength of the screened on-site electron-electron interaction, that is on the Coulomb and exchange integrals U ␣␤ and J ␣␤ : U ␣␤ describes the Coulomb repulsion among opposite spin electrons on the Published in Physical Review B 59 issue 16, R0409-R10412, 1999 which should be used for any reference to this work 1 …”

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confidence: 99%

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Correlation effects in the low-energy region of nickel photoemission spectra

et al. 1999

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The role of on-site correlation in the low-energy excitations of nickel is studied by comparing the results of high-angular and high-energy resolution photoemission spectroscopy with quasiparticle states calculated as a three-body scattering solution of a multiorbital Hubbard model. It is found that correlation effects modify the energy dispersion and spin polarization of electron states and are essential in order to get a quantitative agreement with experimental data.It is well established that the photoemission spectra of narrow-band materials, such as the elements of the d transition-metal series and their compounds, cannot be entirely explained within a one-electron picture, due to the presence of local correlations between electrons in the partially filled d band.1 Band mapping, i.e., the reduction of the measured spectra to a band structure and its comparison with theoretical results can be a powerful tool to directly investigate correlation effects, provided that some important requirements are fulfilled: on the experimental side, highangular and high-energy resolution photoemission techniques are necessary in order to identify quasiparticle energy dispersions and lifetime broadenings associated with the many-body character of the electronic excitations; on the theoretical side, a realistic description of the band structure must be combined with an accurate treatment of many-body electron-electron interactions to account for the mixed itinerant and localized behavior of the valence states.In this paper we present direct evidence of correlation effects in the low binding-energy region of the valence band of nickel. While these effects dominate the high-energy region of the Ni photoemission spectrum with the presence of the well-known 6 eV satellite peak, 2 the electron states near the Fermi energy are commonly believed to be less influenced by many-body interactions; this has to do with the very general properties of low-energy excitations of Fermi liquids, 3 but also with the observation that the Fermi surface of ferromagnetic nickel is nicely reproduced by a singleparticle band structure. 4 All the same, significant discrepancies are known to exist between the observed energy dispersions of some bands and the results of standard singleparticle band calculations; 5 these discrepancies are related to the energy renormalization due to electron-electron interaction. Here we want to investigate these effects in detail in order to get a band mapping of low-energy quasiparticle excitations.A high-resolution photoemission data set was measured at room temperature on a Ni͑110͒ surface. Using He I radiation for excitation (hϭ21.21 eV), energy spectra were taken in 1°steps for a continuous range of polar angles along the ͑001͒ plane, from normal emission ( m ϭ0°) to a polar angle of m ϭ70°off normal. Each spectrum spans a bindingenergy range from Ϫ300 meV ͑above E F ) to 1200 meV ͑below E F ) and was measured with an energy resolution of 35 meV. The angular resolution was set to Ϯ0.5°using an iris aperture in front...

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Three-body scattering theory of correlated hole and electron states

Cited by 39 publications

References 2 publications

A self-consistent, relativistic implementation of the LSDA+DMFT method

A self-consistent, relativistic implementation of the LSDA+DMFT method

Effects of spin-dependent quasiparticle renormalization in Fe, Co, and Ni photoemission spectra:An experimental and theoretical study

Correlation effects in the low-energy region of nickel photoemission spectra

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