Spin-orbit coupling in Fe-based superconductors
  We study the spin resonance peak in recently discovered iron-based superconductors. The resonance peak observed in inelastic neutron scattering experiments agrees well with predicted results for the extended $s$-wave ($s_\pm$) gap symmetry. Recent neutron scattering measurements show that there is a disparity between longitudinal and transverse components of the dynamical spin susceptibility. Such breaking of the spin-rotational invariance in the spin-liquid phase can occur due to spin-orbit coupling. We study the role of the spin-orbit interaction in the multiorbital model for Fe-pnictides and show how it affects the spin resonance feature. 
M.M. Korshunov, Yu.N. Togushova, I. Eremin, P.J. Hirschfeld
cond-mat.supr-con