Imaging the coexistence of superconductivity and a charge density modulation in K0.73Fe1.67Se2 superconductor

Abstract

We report scanning tunneling microscopy studies of the local structural and electronic properties of the iron selenide superconductor K0.73Fe1.67Se2 with TC = 32K. On the atomically resolved FeSe surface, we observe well-defined superconducting gap and the microscopic coexistence of a charge density modulation with root2*root2 periodicity with respect to the original Se lattice. We propose that a possible origin of the pattern is the electronic superstructure caused by the block antiferromagnetic ordering of the iron moments. The widely expected iron vacancy ordering is not observed, indicating that it is not a necessary ingredient for superconductivity in the intercalated iron selenides.

16 pages, 5 figures

References in corpus (16)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Superconductivity at 36 K in beta-Fe1.01Se with the compression of the interlayer separation under pressure
• To What Extent Iron-Pnictide New Superconductors Have Been Clarified: A Progress Report
• A `checkerboard' electronic crystal state in lightly hole-doped Ca_{2-x}Na_{x}CuO_{2}Cl_{2}
• 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
• Superconductivity at 32 K in single crystal Rb${}_{0.78}$Fe${}_2$Se${}_{1.78}$}
• Phase Separation and Magnetic Order in K-doped Iron Selenide Superconductor
• Scanning Tunneling Spectroscopy and Vortex Imaging in the Iron-Pnictide Superconductor BaFe${}_{1.8}$Co${}_{0.2}$As${}_2$
• Transport properties of the new Fe-based superconductor KxFe2Se2 (Tc = 33 K)
• Intrinsic phase separation in superconducting K0.8Fe1.6Se2 (Tc= 31.8 K) single crystals
• Iron vacancy superstructure and possible room temperature antiferromagnetic order in superconducting Cs_{y}Fe_{2-x}Se_2
• Mott transition in Modulated Lattices and Parent Insulator of (K,Tl)yFexSe2 Superconductors
• Electronic Structure and Mott Localization in Iron Deficient TlFe${}_{1.5}$Se${}_2$ with Superstructures
• Collapse of the Fe-vacancy order and successive phase transitions in superconducting KxFe2-ySe2 (0.7 \leg x \leg 0.8, 0.2 \leg y \leg 0.3)

Cited by in corpus (24)

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• Reciprocal-space structure and dispersion of the magnetic resonant mode in the superconducting phase of Rb(x)Fe(2-y)Se2 single crystals
• Superconductivity at 44 K in K intercalated FeSe system with excess Fe
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• Superconductivity dichotomy in K-coated single and double unit cell FeSe films on SrTiO3
• Conformity of spin fluctuations in alkali-metal iron selenide superconductors inferred from the observation of a magnetic resonant mode in K(x)Fe(2-y)Se(2)
• ARPES measurements of the superconducting gap of Fe-based superconductors and their implications to the pairing mechanism
• Dependence of superconductivity in CuxBi2Se3 on quenching conditions
• Intrinsic crystal phase separation in antiferromagnetic superconductor RbyFe2-xSe2: a diffraction study
• Identification of prototypical Brinkman-Rice Mott physics in a class of iron chalcogenides superconductors
• Macroscopic phase segregation in superconducting K0.73Fe1.67Se2 as seen by muon spin rotation and infrared spectroscopy
• Phase co-existence and structured diffuse scattering seen by X-ray 3D mapping of reciprocal space for Cs0.8Fe1.6Se2
• Pairing insights in iron-based superconductors from scanning tunneling microscopy
• Charge order driven by multiple-Q spin fluctuations in heavily electron-doped iron selenide superconductors
• Two-dimensional Cs-vacancy superstructure in iron-based superconductor $C{s}_{0.8}F{e}_{1.6}S{e}_2$
• Checkerboard order state in superconducting FeSe/SrTiO3(001) monolayer
• Band-filling and correlation controlling electronic properties and magnetism in K${}_x$Fe${}_{2-y}$Se${}_2$: A slave boson study
• Possible Way to Make MgFeGe a New Fe-based Superconductor
• Weak Spin Fluctuation with Finite Wave Vector and Superconducting Gap Symmetry in KxFe2-ySe2: 77Se Nuclear Magnetic Resonance
• Driven charge density modulation by spin density wave and their coexistence interplay in SmFeAsO: A first-principles study