Phonon spectrum of SrFe2As2 determined using multizone phonon refinement

Abstract

The ferropnictide superconductors exhibit a sensitive interplay between the lattice and magnetic degrees of freedom, including a number of phonon modes that are much softer than predicted by nonmagnetic calculations using density functional theory (DFT). However, it is not known what effect, if any, the long-range magnetic order has on phonon frequencies above 23 meV, where several phonon branches are very closely spaced in energy and it is challenging to isolate them from each other. We measured these phonons using inelastic time-of-flight neutron scattering in ~40 Brillouin zones, and developed a technique to determine their frequencies. We find this method capable of determining phonon energies to ~0.1 meV accuracy, and that the DFT calculations using the experimental structure yield qualitatively correct energies and eigenvectors. We do not find any effect of the magnetic transition on these phonons.

To be published in Physical Review B

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Cited by in corpus (8)

• HORACE: software for the analysis of data from single crystal spectroscopy experiments at time-of-flight neutron instruments
• Close correlation between magnetic properties and the soft phonon mode of the structural transition in BaFe${}_2$As${}_2$ and SrFe${}_2$As${}_2$
• Effect of magnetism on lattice dynamics in SrFe${}_2$As${}_2$ as seen via high resolution inelastic x-ray scattering
• Competing Electronic Phases near the Onset of Superconductivity in Hole-doped SrFe2As2
• Phonon spectrum of underdoped ${\text{HgBa}}_2{\text{CuO}}_{4+\delta }$ investigated by neutron scattering
• Lattice dynamics in the double-helix antiferromagnet FeP
• Automating Analysis of Neutron Scattering Time-of-Flight Single Crystal Phonon Data
• Occupational Disorder as the Origin of Flattening of the Acoustic Phonon Branches in the Clathrate Ba${}_8$Ga${}_{16}$Ge${}_{30}$