Enhanced superconductivity and moderate spin fluctuations suppressed at low energies in heavily electron-doped La1111-based superconductor

Abstract

To elucidate the origin of re-enhanced high-$T_c$ phase in the heavily electron-doped Fe-pnictides, systematic ${}^{75}$As NMR studies are performed on heavily electron-doped LaFe$Pn$O${}_{0.75}$H${}_{0.25}$ by controlling the pnictogen height ($h_{Pn}$) from the Fe plane through the substitution at $Pn$(=As) site with Sb or P. The measurements of nuclear spin relaxation rate (1/$T_1$) and Knight shift ($K$) reveal that the moderate spin fluctuations at high temperatures are suppressed toward low temperatures. Such characteristic spin fluctuations with gap like feature at low energies are more enlarged in higher $T_c$ compounds with higher $h_{Pn}$, while those are totally suppressed in non-superconducting compounds with lower $h_{Pn}$. This implies that the contribution of the finite energy part in the spin fluctuation spectrum is crucial for enhancing $T_c$ in the heavily electron-doped regime. This is in contrast to many cases of typical Fe-based compounds with hole and electron Fermi surfaces of similar sizes, where the spin fluctuations at low energies develop significantly at low temperatures. The features in the heavily electron-doped states are discussed in relation with the characteristics of the faint hole Fermi surface derived from $d_{xy}$ orbital that rises when $h_{Pn}$ is high, together with the enhanced electron correlation effects.

arXiv comment6 pages, 4 figures, Accepted for publication in Phys. Rev. B

References in corpus (49)

• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3
• Phase Diagram and High Temperature Superconductivity at 65 K in Tuning Carrier Concentration of Single-Layer FeSe Films
• Pnictogen height as a possible switch between high-T_c nodeless and low-T_c nodal pairings in the iron based superconductors
• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• The electronic phase diagram of the LaO1-xFxFeAs superconductor
• Iron-Based Superconductors: current status of materials and pairing mechanism
• Structure determination and coexistence of superconductivity and antiferromagnetic order in (Li0.8Fe0.2)OHFeSe
• Superconductivity at 32 K in single crystal Rb${}_{0.78}$Fe${}_2$Se${}_{1.78}$}
• Observation of superconductivity at 30 K~46 K in AxFe2Se2 (A = Li, Na, Ba, Sr, Ca, Yb, and Eu)
• Synthesis and crystal growth of Cs0.8(FeSe0.98)2: a new iron-based superconductor with Tc=27K
• Comparison of Ab initio Low-Energy Models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe and FeTe: Electron Correlation and Covalency
• Contrasting Spin Dynamics Between Underdoped and Overdoped Ba(Fe[1-x]Co[x])2As2
• Two-dome structure in electron-doped iron arsenide superconductors
• Superconductivity at 32K and anisotropy in Tl0.58Rb0.42Fe1.72Se2 crystals
• Transport properties of the new Fe-based superconductor KxFe2Se2 (Tc = 33 K)
• Bipartite magnetic parent phases in the iron-oxypnictide superconductor
• NMR Study in the Iron-Selenide Rb0.74Fe1.6Se2: Determination of the Superconducting Phase as Iron Vacancy-Free Rb0.3Fe2Se2
• Superconductivity in LaFeAs${}_{1-x}$P${}_x$O: effect of chemical pressures and bond covalency
• Superconductivity at Tc = 44 K in LixFe2Se2(NH3)y
• New Li-Ethylenediamine-Intercalated Superconductor Li${}_x$(C${}_2$H${}_8$N${}_2$)${}_y$Fe${}_{2-z}$Se${}_2$ with $T_c$ = 45 K
• Synthesis and post-annealing effects of alkaline-metal-ethylenediamine-intercalated superconductors Ax(C2H8N2)yFe2-zSe2 (A = Li, Na) with Tc = 45 K
• 77Se NMR Investigation of the K(x)Fe(2-y)Se(2) High Tc Superconductor (Tc=33K)
• Finite energy spin fluctuation as a pairing glue in systems with coexisting electron and hole bands
• Antiferromagnetic Spin Fluctuation above the Superconducting Dome and the Full-Gaps Superconducting State in LaFeAsO1-xFx Revealed by 75As-Nuclear Quadrupole Resonance
• 77Se NMR study of pairing symmetry and spin dynamics in KyFe2-xSe2
• High T_c superconductivity due to coexisting wide and narrow bands: A fluctuation exchange study on the Hubbard ladder as a test case
• Pressure versus concentration tuning of the superconductivity in Ba(Fe(1-x)Cox)2As2
• Detection of antiferromagnetic ordering in heavily doped LaFeAsO1-xHx pnictide superconductors using nuclear-magnetic-resonance techniques
• New Superconducting Phase of Li${}_x$(C${}_6$H${}_{16}$N${}_2$)${}_y$Fe${}_{2-z}$Se${}_2$ with $T_{\text{c}}$ = 41 K Obtained through the Post-Annealing
• New Superconductivity Dome in LaFeAsO${}_{1-x}$F${}_x$ Accompanied by Structural Transition
• Evolution of the Phase Diagram of LaFeP${}_{1-x}$As${}_x$O${}_{1-y}$F${}_y$ ($y$ = 0 -- 0.1)
• Emergence of Novel Antiferromagnetic Order Intervening between Two Superconducting Phases in LaFe(As_1-x_P_x_)O: 31P-NMR Studies
• Wide applicability of high $T_c$ pairing originating from coexisting wide and incipient narrow bands in quasi one dimension
• Possible Superconducting Symmetry and Magnetic Correlations in K0.8Fe2Se2: A 77Se-NMR Study
• Relationship between Superconductivity and Antiferromagnetism in LaFe(As${}_{1-x}$P${}_x$)O Revealed by ${}^{31}$P-NMR
• Ab initio Studies of Magnetism in the Iron Chalcogenides FeTe and FeSe
• Strongly enhanced superconductivity due to finite energy spin fluctuations induced by an incipient band : a FLEX study on the bilayer Hubbard model with vertical and diagonal interlayer hoppings
• Enhancement of Superconducting Transition Temperature Due to Antiferromagnetic Spin Fluctuations in Iron-pnictides LaFe(As_{1-x}P_x)(O_{1-y}F_y) : 31P-NMR Studies
• Quantum critical behavior in heavily doped LaFeAsO${}_{1-x}$H${}_x$ pnictide superconductors analyzed using nuclear magnetic resonance
• Two Fermi surface states and two $T_{\mathrm{c}}$-rising mechanisms revealed by transport properties in $R$FeP${}_{1-x}$As${}_x$O${}_{0.9}$F${}_{0.1}$ ($R$=La, Pr and Nd)
• Origin of Tc Enhancement Induced by Doping Yttrium and Hydrogen into LaFeAsO-based Superconductors: 57Fe, 75As, 139La, and 1H-NMR Studies
• Superconductivity and normal state properties of single-crystalline Tl0.47Rb0.34Fe1.63Se2 as seen via 77Se and 87Rb NMR
• Multiple Antiferromagnetic Spin Fluctuations and Novel Evolution of Tc in Iron-based superconductors LaFe(As1-xPx)(O1-yFy) revealed by 31P-NMR Studies
• Effect of the isoelectronic substitution of Sb for As on the magnetic and structural properties of LaFe(As1-xSbx)O
• Three superconducting phases with different categories of pairing in hole- and electron-doped LaFeAs${}_{1-x}$P${}_x$O
• Importance of dxy orbital and electron correlation in iron-based superconductors revealed by phase diagram for 1111-system
• NMR evidence for an intimate relationship between antiferromagnetic spin fluctuations and extended s-wave superconductivity in mono-crystalline SrFe2(As_{1-x}P_{x})2
• Superconductivity by Hidden Spin Fluctuations in Electron-Doped Iron Selenide
• High-$T_c$ Iron-phosphide Superconductivity Enhanced by Reemergent Antiferromagnetic Spin Fluctuations in (Sr${}_4$Sc${}_2$O${}_6$)Fe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ probed by NMR

Cited by in corpus (1)

• Dynamics of orbital degrees of freedom probed via isotope ${}^{121,123}$ Sb nuclear quadrupole moments in Sb-substituted iron-pnictide superconductors