The theory of indirect resonant inelastic X-ray scattering on magnonsJ. van den Brink
Institute-Lorentz for Theoretical Physics, Universiteit Leiden - P.O. Box 9506, 2300 RA Leiden, The Netherlands and Institute for Molecules and Materials, Radboud Universiteit Nijmegen - P.O. Box 9010, 6500 GL Nijmegen, The Netherlands
received 27 June 2007; accepted in final form 13 September 2007; published November 2007
published online 23 October 2007
Recent experiments reveal indirect resonant inelastic X-ray scattering (RIXS) to be a new probe of spin dynamics. Here I derive the cross-section for magnetic RIXS and determine the momentum-dependent four-spin correlation function that it measures. These results show that this technique offers information on spin dynamics that is complementary to, e.g., neutron scattering. As an example the RIXS spectrum of Heisenberg antiferromagnets is calculated by considering a half filled single band Hubbard model at strong coupling and zero temperature. It turns out that only scattering processes that involve at least two magnons are allowed. Other selection rules imply that the scattering intensity vanishes for specific transferred momenta q, in particular for q = 0. All results agree very well with recent experimental data.
78.70.-g - Interactions of particles and radiation with matter.
71.27.+a - Strongly correlated electron systems; heavy fermions.
© Europhysics Letters Association 2007