Local approach to electron correlations in ferromagnetic nickel

Igarashi, Jun–ichi; Unger, P.P.; Hirai, Kunitomo; Fulde, Peter

doi:10.1103/physrevb.49.16181

Cited by 58 publications

(31 citation statements)

References 37 publications

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“…The aspects of the majority and minority spin bands observed in Fig. 3a and b qualitatively agree with the calculation [11].…”

Section: Spin and Angle-resolved Photoemission Spectra Of Ni(110)supporting

confidence: 79%

Spin-Resolved Photoemission Spectroscopy

Kakizaki

1997

Acta Phys. Pol. A

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The spin-resolved photoemission spectroscopy is utilized to study the spin dependent electronic structures of solids and solid surfaces. The spinand angle-resolved valence band spectra of ferromagnetic Ni are investigated by comparing with an atomic model and a one-electron band calculation. The electron correlation effects which appear in the spin-resolved photoemission spectra are discussed. The spin dependent electronic structures of S atoms adsorbed on Fe(100) surface are also investigated.

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“…The aspects of the majority and minority spin bands observed in Fig. 3a and b qualitatively agree with the calculation [11].…”

Section: Spin and Angle-resolved Photoemission Spectra Of Ni(110)supporting

confidence: 79%

Spin-Resolved Photoemission Spectroscopy

Kakizaki

1997

Acta Phys. Pol. A

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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%

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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“…17. It can be expected that the consideration of self-energy corrections as was done recently by calculating the three-body scattering contributions 36,37 improves the situation and allows one to work with real correlation parameters instead of fitted ones. Our main goal here was the assignment of peaks and not the determination of parameters.…”

Section: Discussionmentioning

confidence: 99%

Analysis of the valence-band photoemission spectrum ofSr2CuO2Cl
Hayn
¹
,
Rösner
²
,
Yushankhai
³

et al. 1999
Phys. Rev. B
25
0
10
0
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Band structure calculations have been used to identify the different bands contributing to the polarisation-dependent photoemission spectra of the undoped model cuprate Sr2CuO2Cl2 at the high-symmetry points of the CuO2 plane Γ, (π/a, 0) and (π/a, π/a) and along the high-symmetry directions Γ − (π/a, π/a) and Γ − (π/a, 0). Results from calculations within the local density approximation (LDA) have been compared with calculations taking into account the strong electron correlations by LDA+U, with the result that the experimental order of energy levels at the high-symmetry points is better described by the LDA+U calculation than by the simple LDA. All the main peaks in the photoemission spectra at the high symmetry points could be assigned to different Cu 3d and O 2p orbitals which we have classified according to their point symmetries. The dispersions along the high-symmetry directions were compared with an 11-band tightbinding model which was fitted both to the LDA+U band structure calculation and the angle-resolved photoemission data. The mean field treatment successfully describes the oxygen derived bands but shows discrepancies for the copper ones.

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Local approach to electron correlations in ferromagnetic nickel

Cited by 58 publications

References 37 publications

Spin-Resolved Photoemission Spectroscopy

Spin-Resolved Photoemission Spectroscopy

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

Analysis of the valence-band photoemission spectrum ofSr2CuO2Cl
Hayn
¹
,
Rösner
²
,
Yushankhai
³

et al. 1999
Phys. Rev. B
25
0
10
0
View full text Add to dashboard Cite

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Local approach to electron correlations in ferromagnetic nickel

Cited by 58 publications

References 37 publications

Spin-Resolved Photoemission Spectroscopy

Spin-Resolved Photoemission Spectroscopy

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

Analysis of the valence-band photoemission spectrum ofSr2CuO2ClHayn1, Rösner2, Yushankhai3 et al. 1999Phys. Rev. B250100View full textAdd to dashboardCite

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Analysis of the valence-band photoemission spectrum ofSr2CuO2Cl
Hayn
¹
,
Rösner
²
,
Yushankhai
³

et al. 1999
Phys. Rev. B
25
0
10
0
View full text Add to dashboard Cite