Electron-lattice coupling, orbital stability and the phase diagram of   Ca$_{2-x}$Sr$_x$RuO$_4$
  Hartree-Fock calculations are presented of a theoretical model describing the Sr/CaRuO$_4$ family of compounds. Both commensurate and incommensurate magnetic states are considered, along with orbital ordering and the effect of lattice distortions. For reasonable parameter values, interactions disfavor orbital disproportionation. A coherent description of the observed phase diagram is obtained. 
Satoshi Okamoto and Andrew J. Millis (Department of Physics, Columbia   University)