Metal-Insulator Transition in Mn Perovskite Compounds
  We discuss Mott insulating and metallic phases of a model with $e_g$ orbital degeneracy to understand physics of Mn perovskite compounds. Quantum Monte Carlo and Lanczos diagonalization results are discussed in this model. To reproduce experimental results on charge gap and Jahn-Teller distortions, we show that a synergy between the strong correlation effects and the Jahn-Teller coupling is important. The incoherent charge dynamics and strong charge fluctuations are characteristic of the metallic phase accompanied with critical enhancement of short-ranged orbital correlation near the insulator. 
Yukitoshi Motome(1), Hiroki Nakano(2) and Masatoshi Imada(2) ((1)   Tokyo Inst. Technology, (2) ISSP, Univ. Tokyo)