Effect of Co-doping on the resistivity and thermopower of SmFe1-xCoxAsO (0.0≤x≤0.3)

Okram, G. S.; Kaurav, Netram; Soni, Ajay; Pal, Anand; Awana, V. P. S.

doi:10.1063/1.4766936

Cited by 2 publications

(2 citation statements)

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“…In the x = 0.035 compound, the electron doping, obtained by Co-substitution, pushes it closer to the condition of single-carrier transport and the Seebeck coefficient remains always negative, as expected for a system dominated by electrons. This has been already shown in La(Fe,Co) AsO and Sm(Fe,Co)AsO series of polycrystalline samples, where a departure from the carrier compensation in favour of an electronlike transport due to Co-doping has been demonstrated 20,21 . Figure 2c, d presents the temperature dependence of the strain (ϵ) derivative of the Seebeck coefficient δ(ΔS/T)/δϵ, with ΔS = S(ϵ) − S(ϵ = 0), for the x = 0 and x = 0.035 compound, respectively (the elasto-Seebeck effect of an additional sample with x = 0.01 is reported in Supplementary Note 3 and Supplementary Fig.…”

Section: Introductionsupporting

confidence: 55%

Strain derivative of thermoelectric properties as a sensitive probe for nematicity

et al. 2021

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The nematic instability is an undebatable ingredient of the physics of iron-based superconductors. Yet, its origin remains enigmatic as it involves a fermiology with an intricate interplay of lattice-, orbital-, and spin degrees of freedom. It is well known that thermoelectric transport is an excellent probe for revealing even subtle signatures of instabilities and pertinent fluctuations. In this paper, we report a strong response of the thermoelectric transport properties of two underdoped 1111 iron-based superconductors to a vanishingly small strain. By introducing the strain derivative of the Seebeck and the Nernst coefficients, we provide a description of the nematic order parameter, proving the existence of an anisotropic Peltier-tensor beside an anisotropic conductivity tensor. Our measurements reveal that the transport nematic phenomenology is the result of the combined effect of both an anisotropic scattering time and Fermi surface distortions, pointing out that in a realistic description, abreast of the spin fluctuations also the orbital character is a fundamental ingredient. In addition, we show that nematic fluctuations universally relax in a Curie–Weiss fashion above TS in all the elasto-transport measurements and we provide evidences that nematicity must be band selective.

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Section: Introductionsupporting

confidence: 55%

Strain derivative of thermoelectric properties as a sensitive probe for nematicity

et al. 2021

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“…Angle-resolved photoemission spectroscopy (ARPES) investigations of LiFe1−xCoxAs and NaFe1−xCoxAs also support this scenario in that the width of the dxy-based band is significantly broadened with increasing Co content 20 . In the same manner, the overdoped REFe1−xCoxAsO and Fe1−xCoxSe show Fermi liquid-like behavior as is confirmed by transport measurements [22][23][24] .…”

Section: Resultsmentioning

confidence: 68%

Large-moment antiferromagnetic order in overdoped high- T _c superconductor ¹⁵⁴ SmFeAsO _{1−
x} D _x

Iimura

Okanishi

Matsuishi

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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In iron-based superconductors, high critical temperature (T c ) superconductivity over 50 K has only been accomplished in electron-doped hREFeAsO (hRE is heavy rare earth (RE) element). Although hREFeAsO has the highest bulk T c (58 K), progress in understanding its physical properties has been relatively slow due to difficulties in achieving high-concentration electron doping and carrying out neutron experiments. Here, we present a systematic neutron powder diffraction study of 154 SmFeAsO 1−x D x , and the discovery of a long-range antiferromagnetic ordering with x ≥ 0.56 (AFM2) accompanying a structural transition from tetragonal to orthorhombic. Surprisingly, the Fe magnetic moment in AFM2 reaches a magnitude of 2.73 μ B /Fe, which is the largest in all nondoped iron pnictides and chalcogenides. Theoretical calculations suggest that the AFM2 phase originates in kinetic frustration of the Fe-3d xy orbital, in which the nearest-neighbor hopping parameter becomes zero. The unique phase diagram, i.e., highest-T c superconducting phase adjacent to the strongly correlated phase in electron-overdoped regime, yields important clues to the unconventional origins of superconductivity.high-T c superconductivity | neutron scattering | oxyhydrides | iron-based superconductors | antiferromagnetism C arrier doping is a critical parameter that governs the electronic correlations and ground states in high-T c superconductors. Electronic phase diagrams depicting the evolution of the ground state with doping level not only deepen our understanding of the mechanism of superconductivity but help us extract common trends across different superconducting materials. Until recently, two electronic phases were believed to play a vital role in iron-based superconductivity, i.e., a stripe or double-stripe-type antiferromagnetic (AFM) ordering at a nondoped Fe-3d 6 state and a Mott insulator at a hole-doped Fe-3d 5 state (1-3). The former phase is observed at ambient pressure for the arsenides and telluride, while under high pressures for the selenides, and the AFM fluctuations are a promising candidate for the pairing glue leading to superconductivity (4, 5). On the other hand, the latter picture, confirmed recently in effectively hole-doped Na(Fe 3+ 0.5 Cu + 0.5 )As (6), explains the asymmetric response of the T c and electron correlation to hole and electron doping, where the hole doping (electron doping) into the Fe-3d 6 state tends to enhance (reduce) the T c and the degree of electron correlation, because the system approaches (goes away from) the half-filled Fe-3d 5 state (2).However, these two prevailing scenarios were challenged recently by observations of the behavior of heavily electron-doped FeSe (11-type) and REFeAsO (1111-type), where the T c and electron correlation strength are enhanced rather than weakened with electron doping. In the first of these systems, a quite high T c in the range of 35 K to 41 K was observed, for the electron-doped FeSe using an electric double-layer transistor, which climbs to 46 K to 48 K for ...

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Effect of Co-doping on the resistivity and thermopower of SmFe1-xCoxAsO (0.0≤x≤0.3)

Cited by 2 publications

References 55 publications

Strain derivative of thermoelectric properties as a sensitive probe for nematicity

Strain derivative of thermoelectric properties as a sensitive probe for nematicity

Large-moment antiferromagnetic order in overdoped high- T _c superconductor ¹⁵⁴ SmFeAsO _{1−
x} D _x

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Effect of Co-doping on the resistivity and thermopower of SmFe1-xCoxAsO (0.0≤x≤0.3)

Cited by 2 publications

References 55 publications

Strain derivative of thermoelectric properties as a sensitive probe for nematicity

Strain derivative of thermoelectric properties as a sensitive probe for nematicity

Large-moment antiferromagnetic order in overdoped high- T c superconductor 154 SmFeAsO 1− x D x

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Large-moment antiferromagnetic order in overdoped high- T _c superconductor ¹⁵⁴ SmFeAsO _{1−
x} D _x