On the phonon dispersion relation of single-crystalline $\beta$--FeSe

Abstract

We report on the phonon spectrum probed at the $\beta$--FeSe(001) surface by means of high-resolution electron energy-loss spectroscopy (HREELS). Single crystals of $\beta$--FeSe are cleaved under ultra-high vacuum conditions and are subsequently measured below and above the nematic transition temperature. In total we observe five phonon modes and a phonon cutoff energy of about 40 meV. We identify the origin of each phonon mode based on the selection rules of HREELS and by comparing the experimental results to the ones of \emph{ab initio} density functional calculations. The most prominent phonon modes $A_{1g}$, $B_{1g}$, and $A_{2u}$ appear at energies of about $20.5$ and $25.6$ and $40$ meV, respectively. These phonon modes disperse rather weakly while changing the momentum from zero up to the zone boundary, indicating that they are mainly of optical nature. A comparison between our results and the results of \emph{ab initio} calculations indicates that there must be a mutual interplay between magnetism and lattice dynamics in this compound, similar to the other Fe-based superconductors. Finally, we comment on the role of temperature on the phonon modes probed at the $\bar{\Gamma }$--point. It is observed that both the $B_{1g}$ and $A_{2u}$ phonon modes undergo a downward shift while increasing the temperature from 15 to 300 K. In the case of the $A_{2u}$ mode this shift is about 1.5 meV.

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References in corpus (27)

• Superconductivity in Iron Compounds
• High-temperature superconductivity in iron-based materials
• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Superconductivity at 36 K in beta-Fe1.01Se with the compression of the interlayer separation under pressure
• Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity
• Orbital-driven nematicity in FeSe
• Strong Interplay between Stripe Spin Fluctuations, Nematicity and Superconductivity in FeSe
• Lack of coupling between superconductivity and orthorhombic distortion in stoichiometric single-crystalline FeSe
• Evolution of spin excitations into the superconducting state in FeTe1-xSex
• Frustrated Magnetic Interactions, Giant Magneto-Elastic Coupling, and Magnetic Phonons in Iron-Pnictides
• High energy spin excitations in BaFe2As2
• The origin of nematic order in FeSe
• Strong $(\pi ,0)$ spin fluctuations in $\beta$-FeSe observed by neutron spectroscopy
• Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
• The magnetic excitation spectra in BaFe${}_2$As${}_2$: a two-particle approach within DFT+DMFT
• Raman scattering study of (K${}_x$Sr${}_{1-x}$)Fe${}_2$As${}_2$ ($x$ = 0.0, 0.4)
• Iron isotope effect on the superconducting transition temperature and the crystal structure of FeSe_1-x
• Neutron scattering Measurements of the phonon density of states of FeSe${}_{1-x}$ superconductors
• Interplay between lattice and spin states degree of freedom in the FeSe superconductor: dynamic spin state instabilities
• Anomalous Raman scattering from phonons and electrons of superconducting FeSe${}_{0.82}$
• Phonon, Two-Magnon and Electronic Raman Scattering of Fe1+yTe1-xSex
• Density of Phonon States in Superconducting FeSe as a Function of Temperature and Pressure
• Prominent role of spin-orbit coupling in FeSe
• 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${}_x$
• The influence of spin-phonon coupling on antiferromagnetic spin fluctuations in FeSe under pressure: the First-principles calculations with van der Waals corrections
• Phonon anomalies in some iron-telluride materials
• Nematic magnetoelastic effect contrasted between Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ and FeSe

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• Anomalous contribution to the nematic electronic states from the structural transition in FeSe revealed by time- and angle-resolved photoemission spectroscopy
• Laser-induced coherent control of an electronic nematic quantum phase transition
• Direct evidence of a charge depletion region at the interface of Van der Waals monolayers and dielectric oxides: The case of superconducting FeSe/STO
• Temperature evolution of the Fermi surface of the FeSe monolayer on SrTiO${}_3$