Incommensurate spin fluctuations in hole-overdoped superconductor KFe2As2

Abstract

A neutron scattering study of heavily hole-overdoped superconducting KFe${}_2$As${}_2$ revealed a well-defined low-energy incommensurate spin fluctuation at [$\pi (1\pm 2\delta$),0] with $\delta$ = 0.16. The incommensurate structure differs from the previously observed commensurate peaks in electron-doped $A$Fe${}_2$As${}_2$ ($A$ = Ba, Ca, or Sr) at low energies. The direction of the peak splitting is perpendicular to that observed in Fe(Te,Se) or in Ba(Fe,Co)${}_2$As${}_2$ at high energies. A band structure calculation suggests interband scattering between bands around the $\Gamma$ and X points as an origin of this incommensurate peak. The perpendicular direction of the peak splitting can be understood within the framework of multiorbital band structure. The results suggest that spin fluctuation is more robust in hole-doped than in electron-doped samples, which can be responsible for the appearance of superconductivity in the heavily hole-doped samples.

4 pages, 4 figures

References in corpus (12)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Two-dimensional resonant magnetic excitation in BaFe1.84Co0.16As2
• Three-dimensional Resonance in superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• Symmetry of spin excitation spectra in the tetragonal paramagnetic and superconducting phases of 122-ferropnictides
• Single Crystal Growth and Characterization of the Iron-Based Superconductor KFe2As2 Synthesized by KAs Flux Method
• Theory of itinerant magnetic excitations in the SDW phase of iron-based superconductors
• Interplay between magnetic properties and Fermi surface nesting in iron pnictides
• Possible three dimensional nodes in the $s\pm$ superconducting gap of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Doping dependence of spin fluctuations and electron correlations in iron pnictides