Neutron-scattering measurements of the spin excitations in LaFeAsO and Ba(Fe${}_{0.953}$Co${}_{0.047}$)${}_2$As${}_2$: Evidence for a sharp enhancement of spin fluctuations by nematic order

Abstract

Inelastic neutron scattering was employed to investigate the impact of electronic nematic order on the magnetic spectra of LaFeAsO and Ba(Fe${}_{0.953}$Co${}_{0.047}$)${}_2$As${}_2$. These materials are ideal to study the paramagnetic-nematic state, since the nematic order, signaled by the tetragonal-to-orthorhombic transition at $T_{\mathrm{S}}$, sets in well above the stripe antiferromagnetic ordering at $T_{\mathrm{N}}$. We find that the temperature-dependent dynamic susceptibility displays an anomaly at $T_{\mathrm{S}}$ followed by a sharp enhancement in the spin-spin correlation length, revealing a strong feedback effect of nematic order on the low-energy magnetic spectrum. Our findings can be consistently described by a model that attributes the structural/nematic transition to magnetic fluctuations, and unveils the key role played by nematic order in promoting the long-range stripe antiferromagnetic order in iron pnictides.

6 pages, 5 figures, 66 references, plus one Supplemental Material. Physical Review Letters, Accepted and in production

References in corpus (19)

• High-temperature superconductivity in iron-based materials
• Evidence for an electron nematic phase transition in underdoped iron pnictide superconductors
• To What Extent Iron-Pnictide New Superconductors Have Been Clarified: A Progress Report
• Theory of Electron Nematic Order in LaOFeAs
• Effects of Co substitution on thermodynamic and transport properties and anisotropic $H_{c2}$ in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ single crystals
• Ising and Spin orders in Iron-based Superconductors
• Nematic and meta-nematic transitions in the iron pnictides
• Orbital Order and Spontaneous Orthorhombicity in Iron Pnictides
• Self-Consistent Vertex Correction Analysis for Iron-Based Superconductors: Mechanism of Coulomb-Interaction-Driven Orbital Fluctuations
• Nematic spin correlations in the tetragonal state of uniaxial strained BaFe2-xNixAs2
• Unprecedented anisotropic metallic state in BaFe2As2 revealed by optical spectroscopy
• Coexistence and competition of the short-range incommensurate antiferromagnetic order with superconductivity in BaFe2-xNixAs2
• Magnetoelastic Coupling in the Phase Diagram of Ba1-xKxFe2As2
• Thermopower as sensitive probe of electronic nematicity in iron pnictides
• Thermodynamic phase diagram and phase competition in BaFe2(As1-xPx)2 studied by thermal expansion
• Magnetic excitations in underdoped Ba(Fe1-xCox)2As2 with x=0.047
• Magnetic and lattice coupling in single-crystal SrFe${}_2$As${}_2$: A neutron scattering study
• Crossover from spin-waves to diffusive spin excitations in underdoped Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Magnetoelastic coupling and charge correlation lengths in a twin domain of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ ($x=0.047$): A high-resolution X-ray diffraction study

Cited by in corpus (10)

• Iron-Based Superconductors: current status of materials and pairing mechanism
• Nematicity, magnetism and superconductivity in FeSe
• Spin reorientation and Ce-Mn coupling in antiferromagnetic oxypnictide CeMnAsO
• Effect of nematic order on the low-energy spin fluctuations in detwinned BaFe${}_{1.935}$Ni${}_{0.065}$As${}_2$
• Spin excitations in the nematic phase and the metallic stripe spin-density wave phase of iron pnictides
• The three-dimensional electronic structure of the nematic and antiferromagnetic phases of NaFeAs from detwinned ARPES measurements
• Spin anisotropy due to spin-orbit coupling in optimally hole-doped Ba${}_{0.67}$K${}_{0.33}$Fe${}_2$As${}_2$
• NMR study of nematic spin fluctuations in a detwinned single crystal of underdoped Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Mn-induced magnetic symmetry breaking and its correlation with the metal-insulator transition in bilayered Sr3(Ru1-xMnx)2O7
• Low-energy spin excitations in optimally doped CaFe${}_{0.88}$Co${}_{0.12}$AsF superconductor studied with inelastic neutron scattering