Electronic structure of heavily electron-doped BaFe1.7Co0.3As2studied by angle-resolved photoemission

Sekiba, Y.; Sato, Takafumi; Nakayama, K.; Terashima, Kazuhiko; Richard, P.; Bowen, J. H.; Ding, Hong; Xu, Yueren; Li, L. J.; Cao, Guanghan; Xu, Z. A.; Takahashi, Takashi

doi:10.1088/1367-2630/11/2/025020

Cited by 141 publications

(150 citation statements)

References 30 publications

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“…That means the decrease in the hole pocket size is relatively low compared to the increase in the electron pocket. This observation is not supporting the experimental [19][20][21][22][23]25,30,31] and theoretical [17,24,62] reports on weakly correlated 122-type and 111-type compounds, which suggests that in going from the substitution of Co to Ni to Cu to Zn in the place of Fe, the volume of the Fermi sheets increases and decreases, which is qualitatively consistent with the rigid-band model.…”

Section: Discussioncontrasting

confidence: 76%

“…These studies also point out that with the 3d transition element substitution for Fe, a part of the additional electrons from the transition metal remain localized at the constituents. However, there are several ARPES reports that demonstrate that the Co substitution for Fe donates the charge carriers to the host system according to a rigid band model [19][20][21][22][23]. On the other hand, with the substitution of Ni and Cu for Fe, the additional doping concentration is reduced, while for Zn the additional electrons are completely localized at the Zn ions [17,24].…”

Section: Introductionmentioning

confidence: 99%

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Effect of impurity substitution on band structure and mass renormalization of the correlatedFeTe0.5Se0.5superconductor

et al. 2016

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Using angle-resolved photoemission spectroscopy (ARPES), we studied the effect of the impurity potential on the electronic structure of FeTe 0.5 Se 0.5 superconductor by substituting 10% of Ni for Fe, which leads to an electron doping of the system. We could resolve three hole pockets near the zone center and an electron pocket near the zone corner in the case of FeTe 0.5 Se 0.5 , whereas only two hole pockets near the zone center and an electron pocket near the zone corner are resolved in the case of Fe 0.9 Ni 0.1 Te 0.5 Se 0.5 , suggesting that the hole pocket having predominantly the xy orbital character is very sensitive to the impurity scattering. Upon electron doping, the size of the hole pockets decreases and the size of the electron pockets increases as compared to the host compound. However, the observed changes in the size of the electron and hole pockets are not consistent with the rigid-band model. Moreover, the effective mass of the hole pockets is reduced near the zone center and of the electron pockets is increased near the zone corner in the doped Fe 0.9 Ni 0.1 Te 0.5 Se 0.5 as compared to FeTe 0.5 Se 0.5 . We refer these observations to the changes of the spectral function due to the effect of the impurity potential of the dopants.

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Section: Discussioncontrasting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Effect of impurity substitution on band structure and mass renormalization of the correlatedFeTe0.5Se0.5superconductor

et al. 2016

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“…These paths were chosen as they allow us to compare our results with available ARPES data, in particular those of Refs. 65,[72][73][74] . Concretely, we here show the evolution of the spectral function A( k, ω) as a function of momentum k, at low temperature: T = 20 K, and at half-filling: n = 2 (i.e.…”

Section: B Momentum Dependence Of the Spectral Densitỹmentioning

confidence: 99%

Temperature and doping dependence of normal state spectral properties in a two-orbital model for ferropnictides

et al. 2016

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Using a second-order perturbative Green's functions approach we determined the normal state spectral function A( k, ω) employing a minimal model for ferropnictides. Used before to study magnetic fluctuations and superconducting properties, it includes the two effective bands related to Fe-3d orbitals proposed by S. Raghu et al. [Phys. Rev. B 77, 220503 (R) (2008)], and local intra-and inter-orbital correlations for the effective orbitals. Here, we focus on the normal state electronic properties, in particular the temperature and doping dependence of the total density of states, A(ω), and of A( k, ω) in different Brillouin zone regions, comparing them with existing angle resolved photoemission spectroscopy (ARPES) and theoretical results. We obtain an asymmetric effect of electron and hole doping, quantitative agreement with the experimental chemical potential shifts, as well as spectral weight redistributions near the Fermi level with temperature consistent with the available experiments. In addition, we predict a non-trivial dependence of A(ω) with temperature, exhibiting clear renormalization effects by correlations. Interestingly, investigating the origin of this predicted behaviour by analyzing the evolution with temperature of the k-dependent self-energy obtained in our approach, we could identify a number of Brillouin zone points, not probed by ARPES yet, where the largest non-trivial effects of temperature on the renormalization are predicted for the parent compounds.

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“…In principle, we can achieve this situation in iron pnictide materials via heavy electron doping; however at such large doping superconductivity also disappears. [90] On the other hand, the recently discovered superconductivity in iron-selenide compound in the 122 crystal structure with T c ~ 37 K makes the material realization of this situation possible. [4][5][6] In these materials, the number of Fe vacancies in the crystal acts as a tuning parameter for the electronic states.…”

Section: Similarity Between Kfe 2 As 2 and Cecoin 5 Superconductorsmentioning

confidence: 99%

Pairing symmetries of several iron-based superconductor families and some similarities with cuprates and heavy-fermions

Das

2012

EPJ Web of Conferences

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Abstract. We show that, by using the unit-cell transformation between 1 Fe per unit cell to 2 Fe per unit cell, one can qualitatively understand the pairing symmetry of several families of iron-based superconductors. In iron-pnictides and iron-chalcogenides, the nodeless s ± -pairing and the resulting magnetic resonance mode transform nicely between the two unit cells, while retaining all physical properties unchanged. However, when the electron-pocket disappears from the Fermi surface with complete doping in KFe 2 As 2 , we find that the unitcell invariant requirement prohibits the occurrence of s ± -pairing symmetry (caused by inter-hole-pocket nesting). However, the intra-pocket nesting is compatible here, which leads to a nodal d-wave pairing. The corresponding Fermi surface topology and the pairing symmetry are similar to Ce-based heavy-fermion superconductors. Furthermore, when the Fermi surface hosts only electron-pockets in K y Fe 2-x Se 2 , the interelectron-pocket nesting induces a nodeless and isotropic d-wave pairing. This situation is analogous to the electron-doped cuprates, where the strong antiferromagnetic order creates similar disconnected electron-pocket Fermi surface, and hence nodeless d-wave pairing appears. The unit-cell transformation in K y Fe 2-x Se 2 exhibits that the d-wave pairing breaks the translational symmetry of the 2 Fe unit cell, and thus cannot be realized unless a vacancy ordering forms to compensate for it. These results are consistent with the coexistence picture of a competing order and nodeless d-wave superconductivity in both cuprates and K y Fe 1.6 Se 2 .

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Electronic structure of heavily electron-doped BaFe_1.7Co_0.3As₂studied by angle-resolved photoemission

Cited by 141 publications

References 30 publications

Effect of impurity substitution on band structure and mass renormalization of the correlatedFeTe0.5Se0.5superconductor

Effect of impurity substitution on band structure and mass renormalization of the correlatedFeTe0.5Se0.5superconductor

Temperature and doping dependence of normal state spectral properties in a two-orbital model for ferropnictides

Pairing symmetries of several iron-based superconductor families and some similarities with cuprates and heavy-fermions

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