Probing the Role of Co Substitution in the Electronic Structure of Iron Pnictides

Levy, G.; Sutarto, Ronny; Chevrier, D.; Regier, Tom; Blyth, R. I. R.; Geck, J.; Wurmehl, S.; Harnagea, Luminita; Wadati, H.; Mizokawa, T.; Elfimov, Ilya; Damascelli, A.; Sawatzky, G. A.

doi:10.1103/physrevlett.109.077001

Cited by 61 publications

(50 citation statements)

References 21 publications

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“…30,35 The major disadvantage of such an approach is the high computational effort which limits its possible applications. Using a Korringa-Kohn-Rostoker-Green function (KKR-GF) based method the coherent potential approximation (CPA) is a more straightforward way to account for disorder compared to a supercell calculation but with considerably less computational effort needed.…”

Section: -34mentioning

confidence: 99%

Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase ofBa(Fe1−xCox)2
Derondeau¹,
Polesya²,
Mankovsky³
et al. 2014
Phys. Rev. B
9
1
16
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We present a comprehensive study on the low-temperature orthorhombic phase of Ba(Fe 1-x Co x ) 2 As 2 based on the Korringa-Kohn-Rostoker-Green function approach. Using this bandstructure method in combination with the coherent potential approximation alloy theory we are able to investigate the evolution of the magnetic and electronic properties of this prototype iron pnictide for arbitrary concentrations x, while dealing with the chemical disorder without uncontrolled simplifications by using solely a rigid band shift or the virtual crystal approximation. We discuss the development of the site resolved magnetic moments for the experimentally observed stripe antiferromagnetic order together with the strong electronic anisotropy of the Fermi surface and compare it with angle-resolved photoemission spectroscopy measurements of detwinned crystals. We furthermore calculate magnetic exchange coupling parameters Jij and use them for Monte-Carlo simulations on the basis of the classical Heisenberg model to get an insight on the temperature dependence of the magnetic ordering on the cobalt concentration.

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Section: -34mentioning

confidence: 99%

Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase ofBa(Fe1−xCox)2
Derondeau¹,
Polesya²,
Mankovsky³
et al. 2014
Phys. Rev. B
9
1
16
0
View full text Add to dashboard Cite

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“…There are still extended debates in the literature on the role of Co in inducing superconductivity in Fe-based pnictides [55][56][57][58][59]. Naturally, the Co substituted systems have been widely referred to as electron-doped.…”

Section: Magnetic Properties Of Prfeasomentioning

confidence: 99%

High-pressure flux growth, structural, and superconducting properties ofLnFeAsO (Ln=Pr, Nd, Sm) single cryst

et al. 2012

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Single-crystals of the LnFeAsO (Ln1111, Ln = Pr, Nd, and Sm) family with lateral dimensions up to 1 mm were grown from NaAs and KAs flux at high pressure. The crystals are of good structural quality and become superconducting when O is partially substituted by F (PrFeAsO 1-x F x and NdFeAsO 1-x F x ) or when Fe is substituted by Co (SmFe 1-x Co x AsO).From magnetization measurements, we estimate the temperature dependence and anisotropy of the upper critical field and the critical current density of underdoped PrFeAsO 0.7 F 0.3 crystal with T c ≈ 25 K. Single crystals of SmFe 1-x Co x AsO with maximal T c up to 16.3 K for x ≈ 0.08 were grown for the first time. From transport and magnetic measurements we estimate the critical fields and their anisotropy, and find these superconducting properties to be quite comparable to the ones in SmFeAsO 1-x F x with a much higher T c of ≈ 50 K. The magnetically measured critical current densities are as high as 10 9 A/m 2 at 2 K up to 7 T, with indication of the usual "fishtail" effect. The upper critical field estimated from resistivity measurements is anisotropic with slopes of ∼ -8.7 T/K (H || ab-plane) and ∼ -1.7 T/K (H || c-axis). This anisotropy (∼ 5) is similar to that in other Ln1111 crystals with various higher T c 's.

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“…[17] Nevertheless, this approach now faces strong challenges from recent theoretical and experimental studies. [23][24][25] Further comparative studies of Co, Ni and Cu substitutions are needed and may provide clues regarding both the nature of unconventional superconductivity in the iron pnictides and clarify the effects of M substitutions.…”

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confidence: 99%

Effects of Transition Metal Substitutions on the Incommensurability and Spin Fluctuations inBaFe2As2by Elastic and Inelastic Neutron Scattering

et al. 2012

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The spin fluctuation spectra from nonsuperconducting Cu-substituted, and superconducting Co-substituted, BaFe2As2 are compared quantitatively by inelastic neutron scattering measurements and are found to be indistinguishable. Whereas diffraction studies show the appearance of incommensurate spin-density wave order in Co and Ni substituted samples, the magnetic phase diagram for Cu substitution does not display incommensurate order, demonstrating that simple electron counting based on rigid-band concepts is invalid. These results, supported by theoretical calculations, suggest that substitutional impurity effects in the Fe plane play a significant role in controlling magnetism and the appearance of superconductivity, with Cu distinguished by enhanced impurity scattering and split-band behavior. PACS numbers: 74.70.Xa, 75.30.Fv, 75.30.Kz The role of chemical substitution and its effects on structure, magnetism and superconductivity have become central issues in studies of the iron-pnictide superconductors. [1][2][3][4] This is particularly true for transition-metal (M ) substitution on Fe sites, resulting, nominally, in electron doping of the FeAs layers. When low concentrations of Co, [5,6] Ni, [7,8] Rh,[9, 10] Pt [11] and Pd [9,10] replace Fe, the structural transition temperature (T S ) and the antiferromagnetic (AFM) transition temperature (T N ) are both suppressed to lower values and split with T S > T N . [5-7, 9, 12-14] When the structural and magnetic transitions are suppressed to sufficiently low temperatures, superconductivity emerges below T c and coexists with antiferromagnetism over some range of concentration. Moreover, for Co, Rh and Ni substitutions in BaFe 2 As 2 , neutron diffraction measurements manifest a distinct suppression of the magnetic order parameter in the superconducting regime (T < T c ), which clearly indicates competition between AFM order and superconductivity. [13][14][15][16][17] Cu substitution in BaFe 2 As 2 , in contrast, suppresses the magnetic and structural transitions, but does not support superconductivity [2,8] except, perhaps, below 2 K over a very narrow range in composition.[18] This dichotomy between Co and Ni substitutions and that of Cu is also realized in quaternary fluoroarsenides.[19] However, for Co/Cu co-substitutions in BaFe 2 As 2 , at a fixed non-superconducting Co concentration, the addition of Cu first promotes and then suppresses T c .[18] It has been suggested that previously neglected impurity effects play an important role in this behavior. [8,20] The effects of impurity scattering are also neglected in a simple rigid-band picture for M substitutions, which, at least for Co substitution in BaFe 2 As 2 , seems to adequately account for the evolution of angleresolved photoemission spectroscopy (ARPES) [21], Hall effect, and thermoelectric power (TEP) measurements with concentration.[22] The rigid-band model has also been used successfully to model the suppression of the AFM transition temperature and ordered moment in Ba(Fe 1−x Co x ) 2 As 2 for "u...

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Probing the Role of Co Substitution in the Electronic Structure of Iron Pnictides

Cited by 61 publications

References 21 publications

Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase ofBa(Fe1−xCox)2
Derondeau¹,
Polesya²,
Mankovsky³
et al. 2014
Phys. Rev. B
9
1
16
0
View full text Add to dashboard Cite

Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase ofBa(Fe1−xCox)2
Derondeau¹,
Polesya²,
Mankovsky³
et al. 2014
Phys. Rev. B
9
1
16
0
View full text Add to dashboard Cite

High-pressure flux growth, structural, and superconducting properties ofLnFeAsO (Ln=Pr, Nd, Sm) single cryst

Effects of Transition Metal Substitutions on the Incommensurability and Spin Fluctuations inBaFe2As2by Elastic and Inelastic Neutron Scattering

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Probing the Role of Co Substitution in the Electronic Structure of Iron Pnictides

Cited by 61 publications

References 21 publications

Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase ofBa(Fe1−xCox)2Derondeau1, Polesya2, Mankovsky3 et al. 2014Phys. Rev. B91160View full textAdd to dashboardCite

Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase ofBa(Fe1−xCox)2Derondeau1, Polesya2, Mankovsky3 et al. 2014Phys. Rev. B91160View full textAdd to dashboardCite

High-pressure flux growth, structural, and superconducting properties ofLnFeAsO (Ln=Pr, Nd, Sm) single cryst

Effects of Transition Metal Substitutions on the Incommensurability and Spin Fluctuations inBaFe2As2by Elastic and Inelastic Neutron Scattering

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Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase ofBa(Fe1−xCox)2
Derondeau¹,
Polesya²,
Mankovsky³
et al. 2014
Phys. Rev. B
9
1
16
0
View full text Add to dashboard Cite

Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase ofBa(Fe1−xCox)2
Derondeau¹,
Polesya²,
Mankovsky³
et al. 2014
Phys. Rev. B
9
1
16
0
View full text Add to dashboard Cite