Hydrostatic and uniaxial pressure dependence of superconducting transition temperature of KFe<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>As<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>single crystals

Bud’ko, Sergey L.; Liu, Yong; Lograsso, Thomas A.; Canfield, Paul C.

doi:10.1103/physrevb.86.224514

Cited by 26 publications

(29 citation statements)

References 49 publications

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“…On Figure 1 we show the C/T data vs T for Ba 0.05 K 0.95 Fe 2 As 2 measured in zero field. The superconducting transition region has a width of about 1 K, which is typical for the overdoped samples of this family 36,[39][40][41] . For the unambiguous determination of the thermodynamic superconducting transition temperature T c we use the isoentropic construction (dotted blue line in the main panel), i.e., we choose T c such as the entropy around the transition is conserved.…”

Section: Resultsmentioning

confidence: 95%

Orbital and Pauli limiting effects in heavily dopedBa0.05K0.95Fe2As2

Zhang¹,

Singh²,

Huang³

et al. 2015

Phys. Rev. B

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We investigated the thermodynamic properties of the Fe-based lightly-disordered superconductor Ba0.05K0.95Fe2As2 in external magnetic field H applied along the FeAs layers (H||ab planes). The superconducting (SC) transition temperature for this doping level is Tc = 6.6 K. Our analysis of the specific heat C(T, H) measured for T < Tc implies a sign change of the superconducting order parameter across different Fermi pockets. We provide experimental evidence for the three components superconducting order parameter. We find that all three components have values which are comparable with the previously reported ones for the stoichiometric compound KFe2As2. Our data for C(T, H) and resistivity ρ(T, H) can be interpreted in favor of the dominant orbital contribution to the pair-breaking mechanism at low fields, while Pauli limiting effect dominates at high fields, giving rise to a gapless superconducting state with only the leading non-zero gap.

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Section: Resultsmentioning

confidence: 95%

Orbital and Pauli limiting effects in heavily dopedBa0.05K0.95Fe2As2

Zhang¹,

Singh²,

Huang³

et al. 2015

Phys. Rev. B

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“…The pressure dependence of T c for our K 1−x Na x Fe 2 As 2 system and the available data in the literature for K-122, 1,2,17,19,21 Cs-122 21 and Rb-122 26 are summarized in Fig. 3a.…”

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confidence: 99%

Superconducting properties ofK1−xNaxFe2As2under pressure

Grinenko¹,

Schottenhamel²,

Wolter³

et al. 2014

Phys. Rev. B

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The effect of hydrostatic pressure and partial Na substitution on the normal-state properties and the superconducting transition temperature (Tc) of K1−xNaxFe2As2 single crystals were investigated. It was found that a partial Na substitution leads to a deviation from the standard T 2 Fermi-liquid behavior in the temperature dependence of the normal-state resistivity. It was demonstrated that non-Fermi liquid like behavior of the resistivity for K1−xNaxFe2As2 and some KFe2As2 samples can be explained by disorder effect in the multiband system with rather different quasiparticle effective masses. Concerning the superconducting state our data support the presence of a shallow minimum around 2 GPa in the pressure dependence of Tc for stoichiometric KFe2As2. The analysis of Tc in the K1−xNaxFe2As2 at pressures below 1.5 GPa showed, that the reduction of Tc with Na substitution follows the Abrikosov-Gor'kov law with the critical temperature Tc0 of the clean system (without pair-breaking) which linearly depends on the pressure. Our observations, also, suggest that Tc of K1−xNaxFe2As2 is nearly independent of the lattice compression produced by the Na substitution. Further, we theoretically analyzed the behavior of the band structure under pressure within the generalized gradient approximation (GGA). A qualitative agreement between the calculated and the recently in de Haas-van Alphen experiments 1 measured pressure dependencies of the Fermi-surface cross-sections has been found. These calculations, also, indicate that the observed minimum around 2 GPa in the pressure dependence of Tc may occur without a change of the pairing symmetry.

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“…[49] or ∂T c /∂p c | 0 ≈ +1.1 K GPa −1 in Ref. [42]. These partial derivatives cancel each other to a considerable degree, yielding a hydrostatic pressure derivative that is negative.…”

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confidence: 99%

“…However, under nonhydrostatic conditions, as already explained in Refs. [32,42], the pressure will be larger along the c axis and smaller in the ab plane. This results in larger values of T c and a modification of the superconducting phase diagram [28].…”

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confidence: 99%

Upper critical field ofKFe2As2under pressure: A test for the change in the superconducting gap structure

et al. 2014

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We report measurements of electrical resistivity under pressure to 5.8 GPa, magnetization to 6.7 GPa, and ac susceptibility to 7.1 GPa in KFe2As2. The previously reported change of slope in the pressure dependence of the superconducting transition temperature Tc(p) at a pressure p * ∼ 1.8 GPa is confirmed, and Tc(p) is found to be nearly constant above p * up to 7.1 GPa. The T -p phase diagram is very sensitive to the pressure conditions as a consequence of the anisotropic uniaxial pressure dependence of Tc. Across p * , a change in the behavior of the upper critical field is revealed through a scaling analysis of the slope of Hc 2 with the effective mass as determined from the A coefficient of the T 2 term of the temperature-dependent resistivity. We show that this scaling provides a quantitative test for the changes of the superconducting gap structure and suggests the development of a kz modulation of the superconducting gap above p * as a most likely explanation.

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Hydrostatic and uniaxial pressure dependence of superconducting transition temperature of KFe2As2single crystals

Cited by 26 publications

References 49 publications

Orbital and Pauli limiting effects in heavily dopedBa0.05K0.95Fe2As2

Orbital and Pauli limiting effects in heavily dopedBa0.05K0.95Fe2As2

Superconducting properties ofK1−xNaxFe2As2under pressure

Upper critical field ofKFe2As2under pressure: A test for the change in the superconducting gap structure

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