Increasing stripe-type fluctuations in $A$Fe${}_2$As${}_2$ ($A$ = K, Rb, Cs) superconductors probed by ${}^{75}$As NMR spectroscopy

Abstract

We report ${}^{75}$As nuclear magnetic resonance measurements on single crystals of RbFe${}_2$As${}_2$ and CsFe${}_2$As${}_2$. Taking previously reported results for KFe${}_2$As${}_2$ into account, we find that the anisotropic electronic correlations evolve towards a magnetic instability in the $A$Fe${}_2$As${}_2$ series (with $A$ = K, Rb, Cs). Upon isovalent substitution with larger alkali ions, a drastic enhancement of the anisotropic nuclear spin-lattice relaxation rate and decreasing Knight shift reveal the formation of pronounced spin fluctuations with stripe-type modulation. Furthermore, a decreasing power-law exponent of the nuclear spin-lattice relaxation rate $(1/T_1{)}_{H\parallel ab}$, probing the in-plane spin fluctuations, evidences an emergent deviation from Fermi-liquid behavior. All these findings clearly indicate that the expansion of the lattice in the $A$Fe${}_2$As${}_2$ series tunes the electronic correlations towards a quantum critical point at the transition to a yet unobserved, ordered phase.

5 pages, 4 figures

References in corpus (36)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Determination of the phase diagram of the electron doped superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Quantum critical point lying beneath the superconducting dome in iron-pnictides
• A Sharp Peak of the Zero-Temperature Penetration Depth at Optimal Composition in BaFe2(As1-xPx)2
• Contrasting Spin Dynamics Between Underdoped and Overdoped Ba(Fe[1-x]Co[x])2As2
• Quantum criticality and nodal superconductivity in the FeAs-based superconductor KFe2As2
• Unconventional superconductivity and antiferromagnetic quantum critical behavior in the isovalent-doped BaFe2(As1-xPx)2
• Satellites and large doping- and temperature-dependence of electronic properties in hole-doped BaFe2As2
• Iron pnictides as a new setting for quantum criticality
• Evidence of Strong Correlations and Coherence-Incoherence Crossover in the Iron Pnictide Superconductor KFe2As2
• Possible Multiple Gap Superconductivity with Line Nodes in Heavily Hole-Doped Superconductor KFe2As2 Studied by 75As-NQR and Specific Heat
• Quasiparticle mass enhancement close to the quantum critical point in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Quantum Criticality in Electron-doped BaFe_{2-x}Ni_xAs_2
• Fermi surface and mass enhancement in KFe${}_2$As${}_2$ from de Haas-van Alphen effect measurements
• Quantum criticality in the iron pnictides and chalcogenides
• Incommensurate spin fluctuations in hole-overdoped superconductor KFe2As2
• 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
• Stripe antiferromagnetic correlations in LaFeAsO1-xFx probed by 75As NMR
• Thermal expansion and Grüneisen parameters of Ba(Fe1-xCox)2As2 - a thermodynamic quest for quantum criticality
• Quantum criticality in AFe2As2 with A = K, Rb, and Cs suppresses superconductivity
• Microscopic nature of correlations in multi-orbital AFe2As2 (A=K, Rb, Cs): Hund's coupling versus Coulomb repulsion
• Potential antiferromagnetic fluctuations in hole-doped iron-pnictide superconductor Ba_{1-x}K_{x}Fe_{2}As_{2} studied by ^{75}As nuclear magnetic
• 75As NMR study of single crystals of the heavily overdoped pnictide superconductors Ba{1-x}KxFe2As2 (x = 0.7 and 1)
• NMR evidence for inhomogeneous nematic fluctuations in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Normal state spin dynamics in the iron-pnictide superconductors BaFe2(As1-xPx)2 and Ba(Fe1-xCox)2As2 probed with NMR measurements
• Calorimetric study in single crystal of CsFe${}_2$As${}_2$
• Angle-resolved NMR: quantitative theory of 75As T1 relaxation rate in BaFe2As2
• Heat transport in RbFe2As2 single crystal: evidence for nodal superconducting gap
• Crossover in the magnetic response of single-crystalline Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ and Lifshitz critical point evidenced by Hall effect measurements
• 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
• Superconductivity emerging from an electronic phase separation in the charge ordered phase of RbFe${}_2$As${}_2$
• Nearly-critical spin and charge fluctuations in KFe2As2 observed by high-pressure NMR
• Evolution of quasiparticle excitations with critical mass enhancement in superconducting AFe2As2 (A = K, Rb, and Cs)
• Constraints on the total coupling strength to bosons in iron based superconductors

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• Charge and nematic orders in AFe${}_2$As${}_2$ (A= Rb,Cs) superconductors
• Dominant in-plane symmetric elastoresistance in CsFe2As2
• Approaching itinerant magnetic quantum criticality through a Hund's coupling induced electronic crossover in the YFe${}_2$Ge${}_2$ superconductor
• Universal relationship between low-energy antiferromagnetic fluctuations and superconductivity in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Mass enhancements and band shifts in strongly hole overdoped Fe-based pnictide superconductors: KFe${}_2$As${}_2$ and CsFe${}_2$As${}_2$
• Mapping out the spin fluctuations in Co-doped LaFeAsO single crystals by NMR
• Elastoresistivity of heavily hole doped 122 iron pnictides superconductors