Effect of electron correlations on spin excitation bandwidth in 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>Ba</mml:mi><mml:mrow><mml:mn>0.75</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi mathvariant="normal">K</mml:mi></mml:mrow><mml:mrow><mml:mn>0.25</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi mathvariant="normal">Fe</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mi>As</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml

Murai, Naoki; Suzuki, Katsuhiro; Ideta, S.; Nakajima, M.; Tanaka, Kiyohisa; Ikeda, Hiroaki; Kajimoto, Ryoichi

doi:10.1103/physrevb.97.241112

Cited by 8 publications

(5 citation statements)

References 58 publications

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“…Overall, the spectral shape is consistent with that in the undoped system [40] which has only the C 2magnetic phase. Similar excitation spectra, with a bandwidth of about 200 meV, have recently been reported for hole-doped Ba 0.75 K 0.25 Fe 2 As 2 [41].…”

supporting

confidence: 83%

“…Some cautions are noteworthy when considering the similarity in Fig. 2 between the two phases: (1) the magnetic ground states are different, (2) our sample must be "twinned" in the C 2 -magnetic phase, (3) the excitations may be best described from neither a purely localmoment nor a purely itinerant point of view [13,[40][41][42][43], and (4) our INS spectra are "orbitally summed", whereas "orbitally resolved" measurements might reveal additional contrast between the two phases [44]. Nevertheless, our result suggests that the C 2 -to-C 4 magnetic phase transition is not directly related to changes in the primary magnetic interactions (local-moment picture), or in the electronic structure far away from the Fermi level (itinerant picture).…”

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confidence: 99%

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Preferred magnetic excitations in Sr$_{1-x}$Na$_x$Fe$_2$As$_2$

Guo,

Yue,

Iida

et al. 2018

Preprint

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We have used inelastic neutron scattering to determine magnetic excitations in a single-crystal sample of Sr1−xNaxFe2As2. The material's two magnetic phases, which differ in their orthorhombic and tetragonal lattice symmetries, share very similar strengths of magnetic interactions as seen from the high-energy excitations. At low energies, excitations polarized along the c axis are suppressed in the tetragonal magnetic phase, in accordance with the associated reorientation of the ordered moments. Although excitations perpendicular to the c axis are still prominent, only the weak caxis response exhibits a spin resonant mode in the superconducting state. Our result suggests that c-axis polarized magnetic excitations are important for the formation of the superconductivity, and naturally explains why the critical temperature is suppressed in the tetragonal magnetic phase.

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confidence: 83%

mentioning

confidence: 99%

Preferred magnetic excitations in Sr$_{1-x}$Na$_x$Fe$_2$As$_2$

Guo,

Yue,

Iida

et al. 2018

Preprint

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“…This discrepancy is a consequence of the incorrect description of correlations in IBSC by the DFT approach. This is a well-know problem, which has been discussed many times in the literature [76][77][78] and can be solved by the band renormalization [79] or the combination of DFT with the dynamic mean field theory (DMFT) [80][81][82][83][84][85][86] . A better inclusion of the correlation effects gives more realistic band structures, ordering of magnetic moments, effective masses as well as Fermi surfaces [87].…”

Section: B Electronic Structurementioning

confidence: 99%

Structural, electronic, and dynamical properties of the tetragonal and collapsed tetragonal phases of KFe2As2

et al. 2019

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Compounds with a tetragonal ThCr2Si2-type structure are characterized by the possibility of the isostructural phase transition from the tetragonal phase to the collapsed tetragonal phase induced by the external pressure. An example of a compound with such a phase transition is KFe2As2, which belongs to the family of the iron-based superconductors. In this paper, we investigate the effects of the phase transition on the structural, electronic, and dynamical properties of this compound. Performing the ab initio calculations, we reproduce the dependence of the lattice constants on pressure and analyze the changes of the inter-atomic distances in the tetragonal and collapsed tetragonal phases. Using the tight binding model with maximally localized Wannier orbitals, we calculate and discuss the influence of pressure on the electronic band structure as well as on the shape of the Fermi surface. We found a precursor of the phase transition in the form of enhancement of overlapping between two Wannier orbitals of As atoms. In order to better understand the superconducting properties of KFe2As2, we study the orbital-projected Cooper pairs susceptibility as a function of pressure. We found a decrease of susceptibility with the increasing pressure in a good qualitative agreement with experimental observation. The structural transition also influences the phonon spectrum of KFe2As2, which exhibits pronounced changes induced by pressure. Some phonon modes related with the vibrations of Fe and As atoms show an anomalous, nonmonotonic dependence on pressure close to the phase transition. *

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“…34 For hole doped Ba 1−x K x Fe 2 AS 2 INS studies were focusing on samples with optimal and overdoped composition, 8,19,[35][36][37] where AFM order is completely suppressed, 30 or on higher energies. 38 For hole-doped Sr 1−x Na x Fe 2 As 2 a single very underdoped compo sition with low T c was studied, 39 which revealed only very weak signature of SRM's. In the underdoped hole-doped regime, there is a second magnetic phase appearing in the o-AFM dome at T reo < T N , where the magnetic moments reorient from in-plane towards out-of-plane alignment, 29,31,40 c.f.…”

Section: Introductionmentioning

confidence: 99%

Strong spin resonance mode associated with suppression of soft magnetic ordering in hole-doped Ba1-xNaxFe2As2

et al. 2019

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Spin-resonance modes (SRM) are taken as evidence for magnetically driven pairing in Fe-based superconductors, but their character remains poorly understood. The broadness, the splitting and the spin-space anisotropies of SRMs contrast with the mostly accepted interpretation as spin excitons. We study hole-doped Ba 1−x Na x Fe 2 As 2 that displays a spin reorientation transition. This reorientation has little impact on the overall appearance of the resonance excitations with a high-energy isotropic and a low-energy anisotropic mode. However, the strength of the anisotropic low-energy mode sharply peaks at the highest doping that still exhibits magnetic ordering resulting in the strongest SRM observed in any Fe-based superconductor so far. This remarkably strong SRM is accompanied by a loss of about half of the magnetic Bragg intensity upon entering the SC phase. Anisotropic SRMs thus can allow the system to compensate for the loss of exchange energy arising from the reduced antiferromagnetic correlations within the SC state.

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Effect of electron correlations on spin excitation bandwidth in Ba0.75K0.25Fe2As2

Cited by 8 publications

References 58 publications

Preferred magnetic excitations in Sr$_{1-x}$Na$_x$Fe$_2$As$_2$

Preferred magnetic excitations in Sr$_{1-x}$Na$_x$Fe$_2$As$_2$

Structural, electronic, and dynamical properties of the tetragonal and collapsed tetragonal phases of KFe2As2

Strong spin resonance mode associated with suppression of soft magnetic ordering in hole-doped Ba1-xNaxFe2As2

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