Magnetism Driven by Anion Vacancies in Superconducting $\alpha$--FeSe${}_{1-x}$

Abstract

To study the microscopic electronic and magnetic interactions in the substoichiometric iron chalcogenide FeSe${}_{1-x}$ which is observed to superconduct at x~1/8 up to $T_c$=27 K, we use first principles methods to study the Se vacancy in this nearly magnetic FeSe system. The vacancy forms a ferrimagnetic cluster of eight Fe atoms, which for the ordered x=1/8 alloy leads to half metallic conduction. Similar magnetic clusters are obtained for FeTe${}_{1-x}$ and for BaFe${}_2$As${}_2$ with an As vacancy, although neither of these are half metallic. Based on fixed spin density results, we suggest the low energy excitations in FeSe${}_{1-x}$ are antiparamagnon-like with short correlation length.

6 pages, 5 embedded figures

References in corpus (5)

• Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2
• Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity
• Superconductivity at 27 K in tetragonal FeSe under high pressure
• Electronic Structure and Doping in BaFe${}_2$As${}_2$ and LiFeAs: Density Functional Calculations
• Half Semimetallic Antiferromagnetism in the Sr${}_2$CrTO${}_6$ System, T=Os, Ru

Cited by in corpus (6)

• Superconductivity at 36 K in beta-Fe1.01Se with the compression of the interlayer separation under pressure
• Density Functional Study of Excess Fe in Fe${}_{1+x}$Te: Magnetism and Doping
• The Stoichiometry of FeSe
• Growth and Superconductivity of FeSex Crystals
• Neutron scattering Measurements of the phonon density of states of FeSe${}_{1-x}$ superconductors
• Pressure effect on superconductivity and magnetism in FeSex