Influence of magnetism on phonons in CaFe$_{2}$As$_{2}$ as seen via inelastic x-ray scattering
ORAL
Abstract
In the iron pnictides, the strong sensitivity of the iron magnetic moment to the arsenic position suggests a significant relationship between phonons and magnetism. We measured the phonon dispersion of several branches in the high-temperature tetragonal phase of CaFe$_{2}$As$_{2}$ using inelastic x-ray scattering on single-crystal samples. These measurements were compared to\textit{ ab initio }calculations of the phonons. Spin-polarized calculations imposing the antiferromagnetic order present in the low-temperature tetragonal phase dramatically improve agreement between theory and experiment. This is discussed in terms of the strong antiferromagnetic correlations that are known to persist in the tetragonal phase.
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