Effect of pressure, temperature, fluorine doping, and rare earth elements on the phonon density of states of LFeAsO studied by nuclear inelastic scattering
We have performed systematic studies of the lattice dynamics in LFeAsO (L = La, Ce, Pr, Nd, Sm) in the parent and in the similar to 10% F-doped compounds as a function of pressure and temperature. We have found that the modifications in the partial Fe density of phonon states are mainly governed by the Fe-As bond length. The change of this bond length explains the change of the Fe density of phono