Neutron scattering patterns show Superconductivity in FeTe0.5Se0.5 likely results from itinerant electron fluctuations

Abstract

The discovery of the Fe pnictide superconductors generated great interest as the structure consists of planes of a magnetic material quite similar to the cuprate superconductors. Fe(Te0.5Se0.5) is a particularly simple system whose planes are isostructural to the FeAs layers found in the originally discovered superconductors of this type. We report here neutron scattering measurements on this material that provide an understanding of the superconductivity. Since the information about the Fermi surface is available both from photoemission and band structure calculations for FeTe, FeSe and other related materials the neutron spectra can be used to see if the itinerant electron picture is valid. The results are consistent with a picture where there are both electron and hole Fermi surfaces that make exact (pi,pi) transitions possible. This would normally favor either a spin or charge density wave state. However, our measurements show the extent of the region where (pi,pi) transitions take place and demonstrate that there are a much larger number of transitions near pi,pi). The near (pi,pi) transitions are observed both above and below Tc and are expected to be strongly pairing. The superconductivity can be attributed to these excitations while the exactly (pi,pi) transitions produce the narrow resonance excitation that appears below Tc.

13 pages, 3 figures

References in corpus (11)

• Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity
• Extreme Sensitivity of Superconductivity to Stoichiometry in FeSe (Fe1+dSe)
• Superconductivity close to magnetic instability in Fe(Se1-xTex)0.82
• Tellurium substitution effect on superconductivity of the alpha-phase Iron Selenide
• First-order magnetic and structural phase transitions in Fe${}_{1+y}$Se${}_x$Te${}_{1-x}$
• Bulk Superconductivity at 14 K in Single Crystals of Fe1+yTexSe1-x
• Substitution Effects on FeSe Superconductor
• Fermi surface nesting induced strong pairing in iron-based superconductors
• Electronic properties of single-crystalline Fe${}_{1.05}$Te and Fe${}_{1.03}$Se${}_{0.30}$Te${}_{0.70}$
• Three-dimensional Resonance in superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• Superconductivity in the PbO-type Structure alpha-FeSe

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• Coupling of electronic and magnetic properties in Fe1+y(Te1-xSex)
• Nano-scale Inhomogeneous Superconductivity in Fe(Te1-xSex) Probed by Nanostructure-transport
• Fermiology of Sr4V2O6Fe2As2: Quasi-Nested Fe vs Mott-Insulating V Orbitals