Lattice Dynamics of LaFeAsO1-xFx and PrFeAsO1-y via Inelastic X-Ray Scattering and First-Principles Calculation

The lattice dynamics of LaFeAsO 1- x F x ( x =0,0.1) and PrFeAsO 1- y ( y ∼0.1) are investigated using inelastic x-ray scattering and ab-initio calculation. Measurements of powder samples provide an approximation to the phonon DOS, while dispersion is measured from a single crystal of PrFeAsO 1- y . A model that agrees reasonably well with all of the data at room temperature is built from results of ab-initio calculations by reducing the strength of the Fe–As bond by 30%.

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