Theory of inelastic x-ray scattering in layered superconductors

This paper gives a theoretical treatment of inelastic x-ray scattering off a layered superconductor. We calculate the scattering probability for different gap symmetries (s and d(x2-y2)) The results show that such an experiment in principle can give an indication as to the symmetry of the gap. In the case of s-wave symmetry and a nearly perfectly nested Fermi surface, we find that final-state interactions enhance the scattering rate at threshold (h) over bar omega=2 Delta. The absolute magnitudes of the scattering rates are, however, rather small. Our results indicate that some further development of the synchrotron light sources most likely is needed before this kind of experiment becomes feasible.