Nanoscale phase separation of antiferromagnetic order and superconductivity in K${}_{0.75}$Fe${}_{1.75}$Se${}_2$

Abstract

We report an in-plane optical spectroscopy study on the iron-selenide superconductor K${}_{0.75}$Fe${}_{1.75}$Se${}_2$. The measurement revealed the development of a sharp reflectance edge below T${}_c$ at frequency much smaller than the superconducting energy gap on a relatively incoherent electronic background, a phenomenon which was not seen in any other Fe-based superconductors so far investigated. Furthermore, the feature could be noticeably suppressed and shifted to lower frequency by a moderate magnetic field. Our analysis indicates that this edge structure arises from the development of a Josephson-coupling plasmon in the superconducting condensate. Together with the transmission electron microscopy analysis, our study yields compelling evidence for the presence of nanoscale phase separation between superconductivity and magnetism. The results also enable us to understand various seemingly controversial experimental data probed from different techniques.

6 figures, published version

References in corpus (20)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Competing Orders and Spin-Density-Wave Instability in La(O${}_{1-x}$F${}_x$)FeAs
• Heavily electron-doped electronic structure and isotropic superconducting gap in AxFe2Se2 (A=K,Cs)
• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• A Novel Large Moment Antiferromagnetic Order in K0.8Fe1.6Se2 Superconductor
• Phase Separation and Magnetic Order in K-doped Iron Selenide Superconductor
• Microstructure and Fe-vacancy ordering in the KFexSe2 superconducting system
• Common Crystalline and Magnetic Structure of superconducting A2Fe4Se5
• Coexistence of Magnetism and Superconductivity in the Iron-based Compound Cs_0.8(FeSe_0.98)_2
• The effect of varying Fe-content on transport properties of K intercalated iron selenide KxFe2-ySe2
• Electronic Structure of Fe-Based Superconductors
• Coexistence of superconductivity and antiferromagnetism in single crystals $A_{0.8}F{e}_{2-y}S{e}_2$ (A= K, Rb, Cs, Tl/K and Tl/Rb): evidence from magnetization and resistivity
• Iron vacancy superstructure and possible room temperature antiferromagnetic order in superconducting Cs_{y}Fe_{2-x}Se_2
• 57-Fe Mossbauer study of magnetic ordering in superconducting K_0.85Fe_1.83Se_2.09 single crystals
• Common Fermi Surface Topology and Nodeless Superconducting Gap in K0.68Fe1.79Se2 and (Tl0.45K0.34)Fe1.84Se2 Superconductors Revealed from Angle-Resolved Photoemission Spectroscopy
• Intrinsic Percolative Superconductivity in KxFe2-ySe2 Single Crystals
• Electronic and magnetic structures of ternary iron selenides AFe${}_2$Se${}_2$ (A=K, Cs, or Tl)
• Infrared spectrum and its implications for the electronic structure of the semiconducting iron selenide K${}_{0.83}$Fe${}_{1.53}$Se${}_2$
• Electronic Structure, Topological Phase Transitions and Superconductivity in (K,Cs)xFe2Se2
• Absence of holelike Fermi surface in superconducting K0.8Fe1.7Se2 revealed by ARPES

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