Coexistence of different electronic phases in the K0.8Fe1.6Se2 superconductor: a bulk-sensitive hard x-rays spectroscopy study

Abstract

We have studied electronic and magnetic properties of the K0.8Fe1.6Se2 superconductor by x-ray absorption and emission spectroscopy. Detailed temperature dependent measurements alongwith a direct comparison with the binary FeSe system have revealed coexisting electronic phases: a majority phase with high spin 3+Fe state and a minority phase with intermediate spin 2+Fe state. The effect of high temperature annealing suggests that the compressed phase with lower spin 2+Fe state is directly related with the high Tc superconductivity in the title system. The results clearly underline glassy nature of superconductivity in the electronically inhomogeneous K0.8Fe1.6Se2, similar to the superconductivity in granular phases.

References in corpus (11)

• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• A review of Fe-chalcogenide superconductors: the simplest Fe-based superconductor
• 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
• Superconductivity and Magnetic Properties of high-quality single crystals of $A_x$Fe${}_2$Se${}_2$ ($A$ = K and Cs)
• Iron vacancy superstructure and possible room temperature antiferromagnetic order in superconducting Cs_{y}Fe_{2-x}Se_2
• Ternary iron selenide K${}_{0.8}$Fe${}_{1.6}$Se${}_2$ is an antiferromagnetic semiconductor
• A study of electronic structure of FeSe${}_{1-x}$Te${}_x$ chalcogenides by Fe and Se K-edge x-ray absorption near edge structure measurements
• Pressure effect on superconductivity of $A_x$Fe${}_2$Se${}_2$ ($A$ = K and Cs)
• Large local disorder in the superconducting K_{0.8}Fe_{1.6}Se_{2} studied by extended x-ray absorption fine structure
• Angular Dependence of X-ray Absorption Spectrum for Field-aligned Fe-based Superconductors

Cited by in corpus (11)

• Spin-state transition in the Fe-pnictides
• Direct observation of nanoscale interface phase in the superconducting chalcogenide K${}_x$Fe${}_{2-y}$Se${}_2$ with intrinsic phase separation
• First-principles study of intermediate-spin ferrous iron in the Earth's lower mantle
• Optical conductivity of iron-based superconductors
• Spectromicroscopy of electronic phase separation in K${}_x$Fe${}_{2-y}$Se${}_2$ superconductor
• Superconductivity and magnetism in RbxFe2-ySe2: Impact of thermal treatment on mesoscopic phase separation
• Local and collective magnetism of EuFe${}_2$As${}_2$
• Temperature dependence of iron local magnetic moment in phase-separated superconducting chalcogenide
• Effective medium approximation and the complex optical properties of the inhomogeneous superconductor K_{0.8}Fe_{2-y}Se_2
• $\mathrm{L}{\mathrm{i}}_{\mathrm{x}}({\mathrm{C}}_5{\mathrm{H}}_5\mathrm{N}{)}_{\mathrm{y}}\mathrm{F}{\mathrm{e}}_{2-\mathrm{z}}\mathrm{S}{\mathrm{e}}_2$: a defect resilient expanded-lattice high-temperature superconductor
• Fluctuating magnetism of Co- and Cu-doped NaFeAs