Phase separation in doped Mott insulators
  Motivated by the commonplace observation of Mott insulators away from integer filling, we construct a simple thermodynamic argument for phase separation in first-order doping-driven Mott transitions. We show how to compute the critical dopings required to drive the Mott transition using electronic structure calculations for the titanate family of perovskites, finding good agreement with experiment. The theory predicts the transition is percolative and should exhibit Coulomb frustration. 
Chuck-Hou Yee and Leon Balents
cond-mat.str-el