Origin of the non-monotonic variance of Tc in the 1111 iron based superconductors with isovalent doping

Abstract

Motivated by recent experimental investigations of the isovalent doping iron-based superconductors LaFe(AsxP1-x)O1-yFy and NdFe(AsxP1-x)O1-yFy we theoretically study the correlation between the local lattice structure, the Fermi surface, the spin fluctuation-mediated superconductivity, and the composition ratio. In the phosphides, the dXZ and dYZ orbitals barely hybridize around the Gamma point to give rise to two intersecting ellipse shape Fermi surfaces. As the arsenic content increases and the Fe-As-Fe bond angle is reduced, the hybridization increases, so that the two bands are mixed to result in concentric inner and outer Fermi surfaces, and the orbital character gradually changes to dxz and dyz, where x-y axes are rotated by 45 degrees from X-Y. This makes the orbital matching between the electron and hole Fermi surfaces better and enhances the spin fluctuation within the dxz/yz orbitals. On the other hand, the hybridization splits the two bands, resulting in a more dispersive inner band. Hence, there is a trade-off between the density of states and the orbital matching, thereby locally maximizing the dxz/yz spin fluctuation and superconductivity in the intermediate regime of As/P ratio. The consistency with the experiment strongly indicate the importance of the spin fluctuation played in this series of superconductors.

arXiv comment17 pages, 5 figures

References in corpus (36)

• Maximally-localized generalized Wannier functions for composite energy bands
• Wannier90: A Tool for Obtaining Maximally-Localised Wannier Functions
• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Maximally-localized Wannier functions for entangled energy bands
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• The superconductivity at 18 K in LiFeAs system
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Pnictogen height as a possible switch between high-T_c nodeless and low-T_c nodal pairings in the iron based superconductors
• Extreme Sensitivity of Superconductivity to Stoichiometry in FeSe (Fe1+dSe)
• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)
• Funtional Renormalization Group Study of the Pairing Symmetry and Pairing Mechanism of the FeAs Based High Temperature Superconductors
• A Numerical Renormalization Group Study of the Superconducting and Spin Density Wave Instabilities in MFeAsO${}_{1-x}$F${}_x$ Compounds
• Comparison of Ab initio Low-Energy Models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe and FeTe: Electron Correlation and Covalency
• Two-dome structure in electron-doped iron arsenide superconductors
• Phase diagram and Gap anisotropy in Iron-Pnictide Superconductors
• Model for the Magnetic Order and Pairing Channels in Fe Pnictide Superconductors
• Bipartite magnetic parent phases in the iron-oxypnictide superconductor
• On the multi-orbital band structure and itinerant magnetism of iron-based superconductors
• Pseudogap and Superconductivity in Iron-Based Layered Superconductor studied by Fluctuation-Exchange Approximation
• Superconductivity at 38 K in Iron-Based Compound with Platinum-Arsenide Layers Ca10(Pt4As8)(Fe2-xPtxAs2)5
• Superconductivity in LaFeAs${}_{1-x}$P${}_x$O: effect of chemical pressures and bond covalency
• New iron-based arsenide oxides (Fe2As2)(Sr4M2O6)(M = Sc, Cr)
• Unified picture of the doping dependence of superconducting transition temperatures in alkali metal/ammonia intercalated FeSe
• Is Fermi-surface nesting the origin of superconductivity in iron pnictides?: A fluctuation-exchange-approximation study
• Model of the Electronic Structure of Electron-Doped Iron-Based Superconductors: Evidence for Enhanced Spin Fluctuations by Diagonal Electron Hopping
• Maximizing Fermi surface multiplicity optimizes superconductivity in iron pnictides
• Emergence of Novel Antiferromagnetic Order Intervening between Two Superconducting Phases in LaFe(As_1-x_P_x_)O: 31P-NMR Studies
• Evolution of the Phase Diagram of LaFeP${}_{1-x}$As${}_x$O${}_{1-y}$F${}_y$ ($y$ = 0 -- 0.1)
• Electronic Structure of Novel Superconductor Ca4Al2O6Fe2As2
• Relationship between Superconductivity and Antiferromagnetism in LaFe(As${}_{1-x}$P${}_x$)O Revealed by ${}^{31}$P-NMR
• 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
• 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)

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• Multiple Antiferromagnetic Spin Fluctuations and Novel Evolution of Tc in Iron-based superconductors LaFe(As1-xPx)(O1-yFy) revealed by 31P-NMR Studies
• 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
• Suppression of superconductivity by spin fluctuations in iron-based superconductors
• 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
• Nodal-to-nodeless superconducting order parameter in LaFeAs${}_{1-x}$P${}_x$O synthesized under high pressure
• Change of Fermi surface states related with two different $T_{\mathrm{c}}$-raising mechanisms in iron pnictide superconductor
• Observation of the bands with $d_{xy}$ orbital character near the Fermi level in NdFeAs${}_{1-x}$P${}_x$O${}_{0.9}$F${}_{0.1}$ using angle-resolved photoemission spectroscopy
• Tuning Superconductivity by Isovalent Antimony Substitution in PrFeAs(O,F)