Interplay between lattice and spin states degree of freedom in the FeSe superconductor: dynamic spin state instabilities

Abstract

Polarized Raman-scattering spectra of superconducting, single-crystalline FeSe evidence pronounced phonon anomalies with temperature reduction. A large 6.5% hardening of the B_1g(Fe) phonon mode is attributed to the suppression of local fluctuations of the iron spin state with the gradual decrease of the iron paramagnetic moment. The ab-initio lattice dynamic calculations support this conclusion. The enhancement of the low-frequency spectral weight above the structural phase transition temperature T_s and its change below T_s is discussed in relation with the opening of an energy gap between low (S=0) and higher spin states which prevents magnetic order in FeSe. The very narrow phonon line widths compared to observations in FeTe suggests the absence of intermediate spin states in the fluctuating spin state manifold in FeSe.

9 pages, 5 figures

References in corpus (22)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Superconductivity at 36 K in beta-Fe1.01Se with the compression of the interlayer separation under pressure
• Superconductivity at 27 K in tetragonal FeSe under high pressure
• Extreme Sensitivity of Superconductivity to Stoichiometry in FeSe (Fe1+dSe)
• The Structural Phase Transition in FeSe (Fe1+dSe)
• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• Why Does Undoped FeSe Become A High Tc Superconductor Under Pressure?
• Spin-orbital frustrations and anomalous metallic state in iron-pnictide superconductors
• A review of Fe-chalcogenide superconductors: the simplest Fe-based superconductor
• Superconductivity at 32 K in single crystal Rb${}_{0.78}$Fe${}_2$Se${}_{1.78}$}
• Crystal structure of the new FeSe1-x superconductor
• The Unprecedented Giant Coupling of Fe-spin State and the As-As Hybridization in Iron-Pnictide
• Effects of magnetism and doping on the electron-phonon coupling in BaFe${}_2$As${}_2$
• Pressure-Induced Effects on the Structure of the FeSe Superconductor
• Raman scattering study of (K${}_x$Sr${}_{1-x}$)Fe${}_2$As${}_2$ ($x$ = 0.0, 0.4)
• Spin-state transition in the Fe-pnictides
• Synthesis, crystal structure and magnetism of beta-Fe1.00(2)Se1.00(3) single crystals
• Neutron scattering Measurements of the phonon density of states of FeSe${}_{1-x}$ superconductors
• Anomalous Raman scattering from phonons and electrons of superconducting FeSe${}_{0.82}$
• Anomalous dependence of the c-axis polarized Fe B${}_{1g}$ phonon mode with Fe and Se concentrations in Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$
• Magnetic properties of FeSe superconductor

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• Probing the direct factor for superconductivity in FeSe-Based Superconductors by Raman Scattering
• Fluctuations and pairing in Fe-based superconductors: Light scattering experiments
• Quadrupolar charge dynamics in the nonmagnetic FeSe${}_{1-x}$S${}_x$ superconductors
• Robust magnetic proximity induced anomalous Hall effect in a room temperature van der Waals ferromagnetic semiconductor based 2D heterostructure
• The electronic structure of Co-substituted $\text{Fe}\text{Se}$ superconductor probed by soft X-ray spectroscopy and density functional theory
• Laser-induced coherent control of an electronic nematic quantum phase transition
• Evolution of lattice, spin, and charge properties across the phase diagram of FeSe${}_{1-x}$S${}_x$
• Evidence of superconductivity-induced phonon spectra renormalization in alkali-doped iron selenides
• Direct evidence of a charge depletion region at the interface of Van der Waals monolayers and dielectric oxides: The case of superconducting FeSe/STO
• Raman spectroscopy of K_xCo_{2-y}Se_2 single crystals near the ferromagnet-paramagnet transition
• Small influence of magnetic ordering on lattice dynamics in TaFe${}_{1.25}$Te${}_3$
• Fluctuating Cooper pairs in FeSe at temperatures exceeding double Tc
• Electronic Structure of $\text{Fe}{\text{Se}}_{1-x}{\text{Te}}_x$ Studied by X-ray Spectroscopy and Density Functional Theory
• Phase separation in iron chalcogenide superconductor Rb0.8+xFe1.6+ySe2 as seen by Raman light scattering and band structure calculations