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Skornyakov, S. L.; Efremov, A. I.; Skorikov, N. A.; Korotin, M. A.; Izyumov, Yu. A.; Анисимов, В. И.; Kozhevnikov, Anton; Vollhardt, D.

doi:10.1103/physrevb.80.092501

Cited by 95 publications

(95 citation statements)

References 44 publications

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“…LDA+DMFT calculations [25,26] show that the role of electronic correlations in iron pnictides, unlike the cuprates, is relatively insignificant. It is reduced to a noticeable renormalization of the effective masses of the electron and hole dispersions, as well as to general "compression" (reduction) of the bandwidth.…”

Section: Electronic Structure Of Iron -Selenium Systemsmentioning

confidence: 99%

Electronic structure of FeSe monolayer superconductors

Некрасов

Павлов

Sadovskiǐ

et al. 2016

Low Temperature Physics

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We review a variety of theoretical and experimental results concerning electronic band structure of superconducting materials based on FeSe monolayers. Three type of systems are analyzed:intercalated FeSe systems A x Fe 2 Se 2−x S x and [Li 1−x Fe x OH]FeSe as well as the single FeSe layer films on SrTiO 3 substrate. We present the results of detailed first principle electronic band structure calculations for these systems together with comparison with some experimental ARPES data. The electronic structure of these systems is rather different from that of typical FeAs superconductors, which is quite significant for possible microscopic mechanism of superconductivity. This is reflected in the absence of hole pockets of the Fermi surface at Γ-point in Brillouin zone, so that there are no "nesting" properties of different Fermi surface pockets. LDA+DMFT calculations show that correlation effects on Fe-3d states in the single FeSe layer are not that strong as in most of FeAs systems. As a result, at present there is no theoretical understanding of the formation of rather "shallow" electronic bands at M points. LDA calculations show that the main difference in electronic structure of FeSe monolayer on SrTiO 3 substrate from isolated FeSe layer is the presence of the band of O-2p surface states of TiO 2 layer on the Fermi level together with Fe-3d states, which may be important for understanding the enhanced T c values in this system. We briefly discuss the implications of our results for microscopic models of superconductivity.

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Section: Electronic Structure Of Iron -Selenium Systemsmentioning

confidence: 99%

Electronic structure of FeSe monolayer superconductors

Некрасов

Павлов

Sadovskiǐ

et al. 2016

Low Temperature Physics

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“…Also, angleresolved photoemission spectra for doped BaFe 2 As 2 exhibit a depletion of spectral weight near the Fermi level that differs from the superconducting gap. 11 To investigate the influence of Coulomb correlations on the electronic properties of iron pnictides, various groups 2,6,[12][13][14][15][16][17][18][19][20][21] have used dynamical mean-field theory 22 (DMFT) combined with single-particle Hamiltonians derived from densityfunctional theory. These calculations typically revealed moderate to strong effective mass enhancement, in agreement with experimental data.…”

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confidence: 99%

“…Similar quasiparticle spectra have been obtained for a variety of pnictides. 6,[13][14][15][16][17][18][19][20][21]26,27 In principle, integer occupancy n = 6 can also sustain a Mott phase. This phase occurs, however, at much larger Coulomb energies.…”

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High-energy pseudogap induced by Hund coupling in a degenerate Hubbard model

Liebsch

2011

Phys. Rev. B

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Hund coupling in the degenerate five-band Hubbard model near n = 6 occupancy is shown to give rise to a significant depletion of spectral weight above the Fermi level. Calculations within dynamical mean-field theory combined with exact diagonalization reveal that this pseudogap is associated with a collective mode in the self-energy caused by spin fluctuations. The pseudogap is remarkably stable over a wide range of Coulomb and exchange energies, but disappears for weak Hund coupling. The implications of this phenomenon for optical spectra of iron pnictides are discussed. Introduction. The discovery of superconductivity in iron pnictides 1 has stimulated intense discussions concerning the role of correlation effects in these compounds. In contrast to high-T c cuprates, which have antiferromagnetic Mott insulators as parent compounds, pnictides are correlated magnetic metals that tend to show significant deviations from Fermi-liquid behavior. Moreover, as a result of the multiband nature of pnictides, the interplay of Coulomb and exchange interactions gives rise to phenomena not found in cuprates. The importance of Hund coupling in pnictides and chalcogenides was recently pointed out in several theoretical 2-6 and experimental studies. [7][8][9] Optical data on paramagnetic LaFePO (Ref. 10) and BaFe 2 As 2 (Refs. 7-9) reveal a high-energy pseudogap not compatible with normal metal behavior. This pseudogap differs fundamentally from the low-energy gap in the antiferromagnetic spin-density wave phase. Also, angleresolved photoemission spectra for doped BaFe 2 As 2 exhibit a depletion of spectral weight near the Fermi level that differs from the superconducting gap. 11 To investigate the influence of Coulomb correlations on the electronic properties of iron pnictides, various groups 2,6,12-21 have used dynamical mean-field theory 22 (DMFT) combined with single-particle Hamiltonians derived from densityfunctional theory. These calculations typically revealed moderate to strong effective mass enhancement, in agreement with experimental data. Correlations were also shown to give rise to nonzero low-energy scattering rates, 13,16,18 indicating bad metallicity. On the other hand, as a result of the complex band structure of pnictides, all five d bands are important, so that the many-body features exhibit a marked orbital dependence. Moreover, the Fe 3d density of states generally shows two main features separated by a deep minimum slightly above the Fermi energy. In view of these multiband characteristics, it is difficult to distinguish genuine many-body features from single-particle properties. For instance, it is presently not clear to what extent pseudogaps in the interacting density of states are induced by Coulomb correlations or band-structure effects.The aim of the present Rapid Communication is to unravel these competing influences. For this purpose we have performed DMFT calculations for a simplified Hamiltonian consisting of five degenerate semielliptical bands. Since the density of states is featureless, corre...

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“…While there are several reports on the electronic correlations in the family of iron based superconductors [2,3], one may consider that the simplicity in FeSe yields the easiness of theoretical handling, and studying the electronic structure of FeSe can provide the further insights into the correlation effects. Based on this motivation, we studied the electronic structure of FeSe using soft x-ray photoemission spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Analysis on photoemission spectrum of superconducting FeSe

Yoshida

Wakita

Okazaki

et al. 2010

Physica C: Superconductivity and its Applications

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In this paper, we present the result of soft x-ray photoemission spectroscopy and its comparison with the density functional calculation. Although local density approximation seems to be a good starting point for describing the electronic structure of FeSe, the simulated spectrum poorly reproduced the structure around E B = 2 eV. This result suggests the necessity of theoretical treatment beyond local density approximation.

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Classification of the electronic correlation strength in the iron pnictides: The case of the parent compoundBaFe2As2

Cited by 95 publications

References 44 publications

Electronic structure of FeSe monolayer superconductors

Electronic structure of FeSe monolayer superconductors

High-energy pseudogap induced by Hund coupling in a degenerate Hubbard model

Analysis on photoemission spectrum of superconducting FeSe

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