Mean-field phase diagram of interacting e_g electrons
  We investigate the magnetic phase diagram of the two-dimensional model for e_g electrons which describes layered nickelates. One finds a generic tendency towards magnetic order accompanied by orbital polarization. For two equivalent orbitals with diagonal hopping such orbitally polarized phases are induced by finite crystal field. 
M. Raczkowski, A. M. Oles, and R. Fresard