Pressure dependence of coherence-incoherence crossover behavior in KFe2As2 observed by resistivity and 75As-NMR/NQR

Abstract

We present the results of ${}^{75}$As nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR), and resistivity measurements in KFe${}_2$As${}_2$ under pressure ($p$). The temperature dependence of the NMR shift, nuclear spin-lattice relaxation time ($T_1$) and resistivity show a crossover between a high-temperature incoherent, local-moment behavior and a low-temperature coherent behavior at a crossover temperature ($T^{\ast }$). $T^{\ast }$ is found to increase monotonically with pressure, consistent with increasing hybridization between localized $3d$ orbital-derived bands with the itinerant electron bands. No anomaly in $T^{\ast }$ is seen at the critical pressure $p_{\mathrm{c}}=1.8$ GPa where a change of slope of the superconducting (SC) transition temperature $T_{\mathrm{c}}(p)$ has been observed. In contrast, $T_{\mathrm{c}}(p)$ seems to correlate with antiferromagnetic spin fluctuations in the normal state as measured by the NQR $1/T_1$ data, although such a correlation cannot be seen in the replacement effects of A in the AFe${}_2$As${}_2$ (A= K, Rb, Cs) family. In the superconducting state, two $T_1$ components are observed at low temperatures, suggesting the existence of two distinct local electronic environments. The temperature dependence of the short $T_{1s}$ indicates nearly gapless state below $T_{\mathrm{c}}$. On the other hand, the temperature dependence of the long component 1/$T_{1L}$ implies a large reduction in the density of states at the Fermi level due to the SC gap formation. These results suggest a real-space modulation of the local SC gap structure in KFe${}_2$As${}_2$ under pressure.

arXiv comment12 pages, 10 figures, accepted for publication in Phys.Rev. B

References in corpus (45)

• The Puzzle of High Temperature Superconductivity in Layered Iron Pnictides and Chalcogenides
• Quantum Criticality in Heavy Fermion Metals
• Nematic order in iron superconductors - who is in the driver's seat?
• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Strong electronic correlations from Hund's coupling
• Antiferromagnetic order and spin dynamics in iron-based superconductors
• High Temperature Superconductivity in Iron Pnictides and Chalcogenides
• FeAs-based superconductivity: a case study of the effects of transition metal doping on BaFe2As2
• Evidence for superconducting gap nodes in the zone-centered hole bands of KFe2As2 from magnetic penetration-depth measurements
• Evidence of Strong Correlations and Coherence-Incoherence Crossover in the Iron Pnictide Superconductor KFe2As2
• Universal heat conduction in the iron-arsenide superconductor KFe2As2 : Evidence of a d-wave state
• Change of pairing symmetry in the iron-based superconductor KFe2As2
• Possible Multiple Gap Superconductivity with Line Nodes in Heavily Hole-Doped Superconductor KFe2As2 Studied by 75As-NQR and Specific Heat
• Calorimetric Evidence of Multiband Superconductivity in Ba(Fe0.925Co0.075)2As2
• Emergent Kondo scaling in iron-based superconductors AFe2As2 (A = K, Rb, Cs)
• Strong Correlations, Strong Coupling and s-wave Superconductivity in Hole-doped BaFe2As2 Single Crystals
• Antiferromagnetism of SrFe2As2 studied by Single-Crystal 75As-NMR
• The pairing state in KFe2As2 studied by measurements of the magnetic vortex lattice
• Nuclear magnetic resonance in the heavy fermion superconductors
• Stripe antiferromagnetic correlations in LaFeAsO1-xFx probed by 75As NMR
• Spontaneous formation of a superconducting and antiferromagnetic hybrid state in SrFe2As2 under high pressure
• Quantum criticality in AFe2As2 with A = K, Rb, and Cs suppresses superconductivity
• Magnetic fluctuations and superconducting properties of CaKFe4As4 studied by 75As NMR
• Potential antiferromagnetic fluctuations in hole-doped iron-pnictide superconductor Ba_{1-x}K_{x}Fe_{2}As_{2} studied by ^{75}As nuclear magnetic
• Upper critical field of KFe2As2 under pressure: A test for the change in the superconducting gap structure
• Evidence for exclusion of the possibility of $d$-wave superconducting-gap symmetry in Ba-doped KFe${}_2$As${}_2$
• Universal V-shaped temperature-pressure phase diagram in the iron-based superconductors KFe2As2, RbFe2As2, and CsFe2As2
• Competing Magnetic Fluctuations in Iron Pnictide Superconductors: Role of Ferromagnetic Spin Correlations Revealed by NMR
• Sudden reversal in the pressure dependence of Tc in the iron-based superconductor CsFe2As2: A possible link between inelastic scattering and pairing symmetry
• Magnetic and superconducting instabilities in a hybrid model of itinerant/localized electrons for iron pnictides
• Multiband Superconductivity in KFe2As2: Evidence for one Isotropic and several Liliputian Energy Gaps
• Heat transport in RbFe2As2 single crystal: evidence for nodal superconducting gap
• Nodal gap in iron-based superconductor CsFe${}_2$As${}_2$ probed by quasiparticle heat transport
• Two distinct superconducting states in KFe${}_2$As${}_2$ under high pressure
• Finding New Superconductors: The Spin-Fluctuation Gateway to High Tc and Possible Room Temperature Superconductivity
• Hydrostatic and uniaxial pressure dependence of superconducting transition temperature of KFe2As2 single crystals
• Superconductivity emerging from an electronic phase separation in the charge ordered phase of RbFe${}_2$As${}_2$
• On the dual role of the d-electrons in iron-pnictides
• Nearly-critical spin and charge fluctuations in KFe2As2 observed by high-pressure NMR
• Superfluid density and superconducting gaps of RbFe_{2}As_{2} as a function of hydrostatic pressure
• ${}^{57}$Fe Mössbauer study of stoichiometric iron based superconductor CaKFe${}_4$As${}_4$: a comparison to KFe${}_2$As${}_2$ and CaFe${}_2$As${}_2$
• Reemergeing electronic nematicity in heavily hole-doped Fe-based superconductors
• Evolution of quasiparticle excitations with critical mass enhancement in superconducting AFe2As2 (A = K, Rb, and Cs)
• Breakdown of single spin-fluid model in heavily hole-doped superconductor CsFe2As2
• Superconducting properties of K${}_{1-x}$Na${}_x$Fe${}_2$As${}_2$ under pressure

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• Unraveling the origin of Kondo-like behavior in the 3$d$-electron heavy-fermion compound YFe${}_2$Ge${}_2$
• Van Hove singularities, chemical pressure and phonons: an angle-resolved photoemission study of KFe${}_2$As${}_2$ and CsFe${}_2$As${}_2$
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