Elementary Excitations in the Symmetric Spin--Orbital Model
  Possible types of elementary excitations in the symmetric spin-orbital model on the a square lattice are analyzed using a spherically symmetric self-consistent approach. The excitation spectra are calculated. The behavior of the corresponding correlation functions depending on the temperature and parameters of the model is studied. A schematic phase diagram is plotted. It is shown that the thermodynamics of the system is mainly determined by elementary excitations with the entangled spin and orbital degrees of freedom. 
M. Y. Kagan, K. I. Kugel, A. V. Mikheyenkov, A. F. Barabanov
cond-mat.str-el