Importance of the Fermi-surface topology to the superconducting state of the electron-doped pnictide Ba(Fe<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:math>Co<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mi>x</mml:mi></mml:msub></mml:math>)<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"

Liu, Chang; Palczewski, Ari; Dhaka, R. S.; Kondo, Takeshi; Fernandes, Rafael M.; Mun, E. D.; Hodovanets, Halyna; Thaler, A.; Schmalian, Joerg; Bud’ko, Sergey L.; Canfield, Paul C.; Kaminski, Adam

doi:10.1103/physrevb.84.020509

Cited by 136 publications

(134 citation statements)

References 25 publications

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“…13,14 These observations rather point toward an intrinsic origin of the transition, for example, due to a change of the Fermi-surface topology as was observed in this doping range with the angle-resolved photoemission spectroscopy (ARPES). 61 A corresponding μSR study of homogeneous Ba 1−x K x Fe 2 As 2 samples in the weakly underdoped regime with 0.5T c, max < T c < T c, max , to the best of our knowledge, is still lacking.…”

Section: Resultsmentioning

confidence: 99%

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2
Bernhard
¹
,
Wang
²
,
Nuccio
³

et al. 2012
Phys. Rev. B
54
22
87
1
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Publication date: 2012 Document VersionPublisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Bernhard, C., Wang, C. N., Nuccio, L., Schulz, L., Zaharko, O., Larsen, J., ... Niedermayer, C. (2012). Muon spin rotation study of magnetism and superconductivity in Using muon spin rotation (μSR) we investigated the magnetic and superconducting properties of a series of Ba(Fe 1−x Co x ) 2 As 2 single crystals with 0 x 0.15. Our study details how the antiferromagnetic order is suppressed upon Co substitution and how it coexists with superconductivity. In the nonsuperconducting samples at 0 < x < 0.04 the antiferromagnetic order parameter is only moderately suppressed. With the onset of superconductivity this suppression becomes faster and it is most rapid between x = 0.045 and 0.05. As was previously demonstrated by μSR at x = 0.055 [P. Marsik et al., Phys. Rev. Lett. 105, 57001 (2010)], the strongly weakened antiferromagnetic order is still a bulk phenomenon that competes with superconductivity. The comparison with neutron diffraction data suggests that the antiferromagnetic order remains commensurate whereas the amplitude exhibits a spatial variation that is likely caused by the randomly distributed Co atoms. A different kind of magnetic order that was also previously identified [C. Bernhard et al., New J. Phys. 11, 055050 (2009)] occurs at 0.055 < x < 0.075 where T c approaches the maximum value. The magnetic order develops here only in parts of the sample volume and it seems to cooperate with superconductivity since its onset temperature coincides with T c . Even in the strongly overdoped regime at x = 0.11, where the static magnetic order has disappeared, we find that the low-energy spin fluctuations are anomalously enhanced below T c . These findings point toward a drastic change in the relationship between the magnetic and superconducting orders from a competitive one in the strongly underdoped regime to a constructive one in near-optimally and overdoped samples.

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Section: Resultsmentioning

confidence: 99%

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2
Bernhard
¹
,
Wang
²
,
Nuccio
³

et al. 2012
Phys. Rev. B
54
22
87
1
View full text Add to dashboard Cite

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“…This demonstrates the dominating role of the FeSe/oxide interface on the high T g in FeSe/Nb:SrTiO 3 or FeSe/Nb:BaTiO 3 . In thick FeCoSe SR films where interfacial effects are negligible, the absence of a gap or a small T g is expected, since heavy electron doping would bring the system to the overdoped regime, where superconductivity diminishes as observed for bulk Fe-HTSs 16,17 .…”

Section: E-e F (Mev) E-e F (Mev)mentioning

confidence: 99%

Tuning the band structure and superconductivity in single-layer FeSe by interface engineering

et al. 2014

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The interface between transition metal compounds provides a rich playground for emergent phenomena. Recently, significantly enhanced superconductivity has been reported for single-layer FeSe on Nb-doped SrTiO 3 substrate. Yet it remains mysterious how the interface affects the superconductivity. Here we use in situ angle-resolved photoemission spectroscopy to investigate various FeSe-based heterostructures grown by molecular beam epitaxy, and uncover that electronic correlations and superconducting gap-closing temperature (T g ) are tuned by interfacial effects. T g up to 75 K is observed in extremely tensile-strained single-layer FeSe on Nb-doped BaTiO 3 , which sets a record high pairing temperature for both Fe-based superconductor and monolayer-thick films, providing a promising prospect on realizing more cost-effective superconducting device. Moreover, our results exclude the direct correlation between superconductivity and tensile strain or the energy of an interfacial phonon mode, and highlight the critical and non-trivial role of FeSe/oxide interface on the high T g , which provides new clues for understanding its origin.

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“…[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.…”

mentioning

confidence: 99%

“…[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 "underdoped" samples.…”

mentioning

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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Importance of the Fermi-surface topology to the superconducting state of the electron-doped pnictide Ba(Fe1−xCox)

Cited by 136 publications

References 25 publications

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2
Bernhard
¹
,
Wang
²
,
Nuccio
³

et al. 2012
Phys. Rev. B
54
22
87
1
View full text Add to dashboard Cite

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2
Bernhard
¹
,
Wang
²
,
Nuccio
³

et al. 2012
Phys. Rev. B
54
22
87
1
View full text Add to dashboard Cite

Tuning the band structure and superconductivity in single-layer FeSe by interface engineering

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

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Importance of the Fermi-surface topology to the superconducting state of the electron-doped pnictide Ba(Fe1−xCox)

Cited by 136 publications

References 25 publications

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2Bernhard1, Wang2, Nuccio3 et al. 2012Phys. Rev. B5422871View full textAdd to dashboardCite

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2Bernhard1, Wang2, Nuccio3 et al. 2012Phys. Rev. B5422871View full textAdd to dashboardCite

Tuning the band structure and superconductivity in single-layer FeSe by interface engineering

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

Contact Info

Product

Resources

About

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2
Bernhard
¹
,
Wang
²
,
Nuccio
³

et al. 2012
Phys. Rev. B
54
22
87
1
View full text Add to dashboard Cite

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2
Bernhard
¹
,
Wang
²
,
Nuccio
³

et al. 2012
Phys. Rev. B
54
22
87
1
View full text Add to dashboard Cite