Spin-excitation anisotropy in the nematic state of detwinned FeSe

Abstract

The origin of the electronic nematicity in FeSe is one of the most important unresolved puzzles in the study of iron-based superconductors. In both spin- and orbital-nematic models, the intrinsic magnetic excitations at ${\mathbf{Q}}_1=(1,0)$ and ${\mathbf{Q}}_2=(0,1)$ of twin-free FeSe are expected to provide decisive criteria for clarifying this issue. Although a spin-fluctuation anisotropy below 10 meV between ${\mathbf{Q}}_1$ and ${\mathbf{Q}}_2$ has been observed by inelastic neutron scattering around $T_c\sim 9$ K ($<<T_s\sim 90$ K), it remains unclear whether such an anisotropy also persists at higher energies and associates with the nematic transition $T_{\mathrm{s}}$. Here we use resonant inelastic x-ray scattering (RIXS) to probe the high-energy magnetic excitations of uniaxial-strain detwinned FeSe and {\BFA}. A prominent anisotropy between the magnetic excitations along the $H$ and $K$ directions is found to persist to $\sim 200$ meV in FeSe, which is even more pronounced than the anisotropy of spin waves in {\BFA}. This anisotropy decreases gradually with increasing temperature and finally vanishes at a temperature around the nematic transition temperature $T_{\mathrm{s}}$. Our results reveal an unprecedented strong spin-excitation anisotropy with a large energy scale well above the $d_{xz}/d_{yz}$ orbital splitting, suggesting that the nematic phase transition is primarily spin-driven. Moreover, the measured high-energy spin excitations are dispersive and underdamped, which can be understood from a local-moment perspective. Our findings provide the much-needed understanding of the mechanism for the nematicity of FeSe and points to a unified description of the correlation physics across seemingly distinct classes of Fe-based superconductors.

arXiv comment15 pages, 5 figures

References in corpus (55)

• Resonant Inelastic X-ray Scattering Studies of Elementary Excitations
• Nematic order in iron superconductors - who is in the driver's seat?
• Theory of Intertwined Orders in High Temperature Superconductors
• Evidence for an electron nematic phase transition in underdoped iron pnictide superconductors
• Divergent nematic susceptibility in an iron arsenide superconductor
• Symmetry breaking orbital anisotropy on detwinned Ba(Fe1-xCox)2As2 above the spin density wave transition
• The Structural Phase Transition in FeSe (Fe1+dSe)
• High Temperature Superconductivity in Iron Pnictides and Chalcogenides
• Ferro-Orbital Order and Strong Magnetic Anisotropy in the Parent Compounds of Iron-Pnictide Superconductors
• Orbital-driven nematicity in FeSe
• Discovery of Orbital-Selective Cooper Pairing in FeSe
• Spin-Orbital Separation in the quasi 1D Mott-insulator Sr2CuO3
• Effect of magnetic frustration on nematicity and superconductivity in Fe chalcogenides
• Ubiquitous signatures of nematic quantum criticality in optimally doped Fe-based superconductors
• Enhancement of superconductivity near a nematic quantum critical point
• Are non-Fermi-liquids stable to Cooper pairing?
• Ironing out the details of unconventional superconductivity
• Strong Interplay between Stripe Spin Fluctuations, Nematicity and Superconductivity in FeSe
• Origin of the tetragonal-to-orthorhombic (nematic) phase transition in FeSe: a combined thermodynamic and NMR study
• Nematicity and quantum paramagnetism in FeSe
• Nematic spin fluid in the tetragonal phase of BaFe2As2
• Magnetic ground state of FeSe
• Nematicity, magnetism and superconductivity in FeSe
• The key ingredients of the electronic structure of FeSe
• Nematic spin correlations in the tetragonal state of uniaxial strained BaFe2-xNixAs2
• Three dimensional collective charge excitations in electron-doped cuprate superconductors
• Antiferroquadrupolar and Ising-Nematic Orders of a Frustrated Bilinear-Biquadratic Heisenberg Model and Implications for the Magnetism of FeSe
• Influence of apical oxygen on the extent of in-plane exchange interaction in cuprate superconductors
• Origin of the Resistivity Anisotropy in the Nematic Phase of FeSe
• A magnetic origin for high temperature superconductivity in iron pnictides
• Persistent high-energy spin excitations in iron pnictide superconductors
• Orbital-dependent Fermi Surface shrinking as a fingerprint of nematicity in FeSe
• Electronic nematic susceptibility of iron-based superconductors
• Sign-reversing orbital polarization in the nematic phase of FeSe due to the $C_2$ symmetry-breaking in the self-energy
• Formation of Hubbard-like bands as a fingerprint of strong electron-electron interactions in FeSe
• Anisotropic spin fluctuations in detwinned FeSe
• Model of Electronic Structure and Superconductivity in Orbitally Ordered FeSe
• Sixfold enhancement of superconductivity in a tunable electronic nematic system
• Orbital-selective superconductivity, gap anisotropy and spin resonance excitations in a multiorbital t-J1-J2 model for iron pnictides
• Evolution of spin excitations from bulk to monolayer FeSe
• Scaling of the superconducting gap with orbital character in FeSe
• Orbital selectivity in electron correlations and superconducting pairing of iron-based superconductors
• Evidences of Mott physics in iron pnictides from x-ray spectroscopy
• Spin Waves in Detwinned BaFe${}_2$As${}_2$
• Direct observation of dispersive lower Hubbard band in iron-based superconductor FeSe
• Itinerant approach to magnetic neutron scattering of FeSe: effect of orbital selectivity
• Uniaxial Pressure Induced Stripe Order Rotation in La${}_{1.88}$Sr${}_{0.12}$CuO${}_4$
• Local and collective magnetism of EuFe${}_2$As${}_2$
• Mechanism for nematic superconductivity in FeSe
• Paramagnon dispersion in $\beta$-FeSe observed by Fe $L$-edge resonant inelastic x-ray scattering
• Reciprocity between local moments and collective magnetic excitations in the phase diagram of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Spin fluctuation anisotropy as a probe of orbital-selective hole-electron quasiparticle excitations in detwinned Ba(Fe1-xCox)2As2
• Effective Exchange Interactions for Bad Metals and Implications for Iron-based Superconductors
• Anisotropic magnetic excitations and incipient Néel order in Ba(Fe${}_{1-x}$Mn${}_x$)${}_2$As${}_2$
• Anisotropic magnetic excitations of a frustrated bilinear-biquadratic spin model -- Implications for spin waves of detwinned iron pnictides

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• Spontaneous orbital polarization in the nematic phase of FeSe
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• Systematic Mapping of Altermagnetic Magnons by Resonant Inelastic X-Ray Circular Dichroism
• Nematic spin correlations pervading the phase diagram of FeSe${}_{1-x}$S${}_x$
• Dispersionless orbital excitations in (Li,Fe)OHFeSe superconductors
• Nematic spectral signatures of the Hund's metal
• Theory of spin-excitation anisotropy in the nematic phase of FeSe obtained from RIXS measurements
• Coexistence of insulator-like paramagnon and metallic spin-orbit exciton modes in SrIrO${}_3$
• Ubiquity of rotational symmetry breaking in superconducting films, from Fe(Te,Se)/Bi${}_2$Te${}_3$ to Nb, and the effect of measurement geometry
• Signatures of three-state Potts nematicity in spin excitations of the van der Waals antiferromagnet FePSe${}_3$