Spin-isotropic continuum of spin excitations in antiferromagnetically ordered Fe${}_{1.07}$Te

Abstract

Unconventional superconductivity typically emerges in the presence of quasi-degenerate ground states, and the associated intense fluctuations are likely responsible for generating the superconducting state. Here we use polarized neutron scattering to study the spin space anisotropy of spin excitations in Fe${}_{1.07}$Te exhibiting bicollinear antiferromagnetic (AF) order, the parent compound of FeTe${}_{1-x}$Se${}_x$ superconductors. We confirm that the low energy spin excitations are transverse spin waves, consistent with a local-moment origin of the bicollinear AF order. While the ordered moments lie in the $ab$-plane in Fe${}_{1.07}$Te, it takes less energy for them to fluctuate out-of-plane, similar to BaFe${}_2$As${}_2$ and NaFeAs. At energies above $E\gtrsim 20$ meV, we find magnetic scattering to be dominated by an isotropic continuum that persists up to at least 50 meV. Although the isotropic spin excitations cannot be ascribed to spin waves from a long-range ordered local moment antiferromagnet, the continuum can result from the bicollinear magnetic order ground state of Fe${}_{1.07}$Te being quasi-degenerate with plaquette magnetic order.

accepted for publication in Phys. Rev. B

References in corpus (21)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• LaFeAsO${}_{1-x}$F${}_x$: A low carrier density superconductor near itinerant magnetism
• Theory of Intertwined Orders in High Temperature Superconductors
• Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family
• Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity
• Neutron tomography of magnetic Majorana fermions in a proximate quantum spin liquid
• Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
• Incommensurate magnetic order in the alpha-Fe(Te,Se) superconductor systems
• First-order magnetic and structural phase transitions in Fe${}_{1+y}$Se${}_x$Te${}_{1-x}$
• High Temperature Superconductivity in Iron Pnictides and Chalcogenides
• Fermi surface topology and low-lying quasiparticle dynamics of parent Fe${}_{1+x}$Te/Se Superconductor by orbital-polarization resolved ARPES
• Bipartite magnetic parent phases in the iron-oxypnictide superconductor
• Spin waves in the $(\pi ,0)$ magnetically ordered iron chalcogenide Fe${}_{1.05}$Te
• Intertwined Orders in Heavy-Fermion Superconductor CeCoIn${}_5$
• Prominent role of spin-orbit coupling in FeSe
• A large moment antiferromagnetic order in overdoped high-Tc superconductor 154SmFeAsO1-xDx
• Soft striped magnetic fluctuations competing with superconductivity in Fe_{1+x}Te
• Anisotropic neutron spin resonance in underdoped superconducting NaFe1-xCoxAs
• Bicollinear Antiferromagnetic Order, Monoclinic Distortion, and Reversed Resistivity Anisotropy in FeTe as a Result of Spin-Lattice Coupling
• Spin anisotropy due to spin-orbit coupling in optimally hole-doped Ba${}_{0.67}$K${}_{0.33}$Fe${}_2$As${}_2$
• Competing spin density wave, collinear, and helical magnetism in Fe1+xTe

Cited by in corpus (5)

• Nature of the spin resonance mode in CeCoIn${}_5$
• Plaquette instability competing with bicollinear ground state in detwinned FeTe
• From mean-field localized magnetism to itinerant spin fluctuations in the "Non-metallic metal" - FeCrAs
• Spin-Excitations Anisotropy in the Bilayer Iron-Based Superconductor CaKFe${}_4$As${}_4$
• Magnetic surface reconstruction in the van-der-Waals antiferromagnet Fe${}_{1+x}$Te