Charge and nematic orders in AFe${}_2$As${}_2$ (A= Rb,Cs) superconductors

Abstract

We discuss the results of ${}^{75}$As Nuclear Quadrupole Resonance (NQR) and muon spin relaxation measurements in AFe${}_2$As${}_2$ (A= Cs, Rb) iron-based superconductors. We demonstrate that the crossover detected in the nuclear spin-lattice relaxation rate $1/T_1$ (around 150 K in RbFe${}_2$As${}_2$ and around 75 K in CsFe${}_2$As${}_2$), from a high temperature nearly localized to a low temperature delocalized behaviour, is associated with the onset of an inhomogeneous local charge distribution causing the broadening or even the splitting of the NQR spectra as well as an increase in the muon spin relaxation rate. We argue that this crossover, occurring at temperatures well above the phase transition to the nematic long-range order, is associated with a charge disproportionation at the Fe sites induced by competing Hund's and Coulomb couplings. In RbFe${}_2$As${}_2$ around 35 K, far below that crossover temperature, we observe a peak in the NQR $1/T_1$ which is possibly associated with the critical slowing down of electronic nematic fluctuations on approaching the transition to the nematic long-range order.

arXiv comment7 pages, 6 figures

References in corpus (34)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• The Puzzle of High Temperature Superconductivity in Layered Iron Pnictides and Chalcogenides
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Nematic order in iron superconductors - who is in the driver's seat?
• Long-range incommensurate charge fluctuations in (Y,Nd)Ba2Cu3O(6+x)
• Magnetic-field-induced charge-stripe order in the high temperature superconductor YBa2Cu3Oy
• Spin-polarized muons in condensed matter physics
• Nematic and meta-nematic transitions in the iron pnictides
• Orbital-driven nematicity in FeSe
• Selective Mottness as a key to iron superconductors
• Orbital-Selective Mott transition out of band degeneracy lifting
• Incipient charge order observed by NMR in the normal state of YBa2Cu3Oy
• Commensurate Itinerant Antiferromagnetism in BaFe2As2: 75As-NMR Studies on a Self-Flux Grown Single Crystal
• Competing charge, spin, and superconducting orders in underdoped YBa2Cu3Oy
• Observation of incipient charge nematicity in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Probing superconducting energy gap from infrared spectroscopy on a Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ single crystal with T${}_c$=37 K
• Electronic Structure of the BaFe${}_2$As${}_2$ Family of Iron Pnictides
• NMR Search for the Spin Nematic State in LaFeAsO Single Crystal
• Emergent Kondo scaling in iron-based superconductors AFe2As2 (A = K, Rb, Cs)
• Charge disproportionation, mixed valence, and Janus effect in multiorbital systems: A tale of two insulators
• Multi-gap superconductivity in single crystals of Ba${}_{0.65}$Na${}_{0.35}$Fe${}_2$As${}_2$: A calorimetric investigation
• Emergence of Orbital Nematicity in the Tetragonal Phase of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Bulk Superconductivity at 2.6 K in Undoped RbFe_2As_2
• Orbital Order and Spin Nematicity in the Tetragonal Phase of Electron-doped Iron-Pnictides NaFe${}_{1-x}$Co${}_x$As
• Nematicity and in-plane anisotropy of superconductivity in $\beta$-FeSe detected by ${}^{77}$Se nuclear magnetic resonance
• 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
• Reemergeing electronic nematicity in heavily hole-doped Fe-based superconductors
• Fast recovery of the stripe magnetic order by Mn/Fe substitution in F-doped LaFeAsO superconductors
• Pressure dependence of coherence-incoherence crossover behavior in KFe2As2 observed by resistivity and 75As-NMR/NQR
• Breakdown of single spin-fluid model in heavily hole-doped superconductor CsFe2As2
• Increasing stripe-type fluctuations in $A$Fe${}_2$As${}_2$ ($A$ = K, Rb, Cs) superconductors probed by ${}^{75}$As NMR spectroscopy
• Nematicity and magnetism in LaFeAsO single crystals probed by ${}^{75}$As nuclear magnetic resonance
• Persistence of slow fluctuations in the overdoped regime of Ba(Fe1-xRhx)2As2 superconductors

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