Structure of spin excitations in heavily electron-doped Li<sub>0.8</sub>Fe<sub>0.2</sub>ODFeSe superconductors.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28743902.
- Also identified by DOI 10.1038/s41467-017-00162-x and PMC identifier 5527112.
- Licence recorded as CC BY.
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Abstract
Heavily electron-doped iron-selenide high-transition-temperature (high-T <sub>c</sub>) superconductors, which have no hole Fermi pockets, but have a notably high T <sub>c</sub>, have challenged the prevailing s <sub>±</sub> pairing scenario originally proposed for iron pnictides containing both electron and hole pockets. The microscopic mechanism underlying the enhanced superconductivity in heavily electron-doped iron-selenide remains unclear. Here, we used neutron scattering to study the spin excitations of the heavily electron-doped iron-selenide material Li<sub>0.8</sub>Fe<sub>0.2</sub>ODFeSe (T <sub>c</sub> = 41 K). Our data revealed nearly ring-shaped magnetic resonant excitations surrounding (π, π) at ∼21 meV. As the energy increased, the spin excitations assumed a diamond shape, and they dispersed outward until the energy reached ∼60 meV and then inward at higher energies. The observed energy-dependent momentum structure and twisted dispersion of spin excitations near (π, π) are analogous to those of hole-doped cuprates in several aspects, thus implying that such spin excitations are essential for the remarkably high T <sub>c</sub> in these materials.The microscopic mechanism underlying an enhanced superconductivity in electron-doped iron selenide superconductor remains unclear. Here, Pan et al. report the spin excitations of Li<sub>0.8</sub>Fe<sub>0.2</sub>ODFeSe, revealing analogous momentum structure and dispersion to hole-doped cuprates.