Spin and charge dynamics ruled by antiferromagnetic order in iron pnictide superconductors

We examine the spin and charge excitations in antiferromagnetic iron pnictides by mean-field calculations with a random-phase approximation in a five-band itinerant model. The calculated excitation spectra reproduce well spin-wave dispersions observed in inelastic neutron scattering with a realistic magnetic moment for CaFe(2)As(2). A particle-hole gap is found to be crucial to obtain consistent results; we predict the spin wave in LaFeAsO disappears at a lower energy than in CaFe(2)As(2). We analyze that the charge dynamics to make predictions for resonant inelastic x-ray scattering spectra.