Phonon Density of States of LaFeAsO1-xFx

cond-mat.supr-con

/ Authors

A. D. Christianson, M. D. Lumsden, O. Delaire, M. B. Stone, D. L. Abernathy, M. A. McGuire, A. S. Sefat, R. Jin, B. C. Sales, D. Mandrus

and 9 more authors

E. D. Mun, P. C. Canfield, J. Y. Y. Lin, M. Lucas, M. Kresch, J. B. Keith, B. Fultz, E. A. Goremychkin, R. J. McQueeney

/ Abstract

We have studied the phonon density of states (PDOS) in LaFeAsO1-xFx with inelastic neutron scattering methods. The PDOS of the parent compound(x=0) is very similar to the PDOS of samples optimally doped with fluorine to achieve the maximum Tc (x~0.1). Good agreement is found between the experimental PDOS and first-principle calculations with the exception of a small difference in Fe mode frequencies. The PDOS reported here is not consistent with conventional electron-phonon mediated superconductivity.