Self-consistent description of simplified pseudospin-electron model
  A method of the self-consistent calculation of the thermodynamical and correlation functions is presented.   This approach is based on the GRPA (generalized random phase approximation) scheme with the inclusion of the mean field corrections.   The numerical research shows that interaction between the electron and pseudospin subsystems leads to the possibility of the dipole (pseudospin) and charge-density instabilities as well as phase separation into the uniform and/or chess-board phases. 
I.V. Stasyuk, A.M. Shvaika, and K.V. Tabunshchyk