Phase Separation Induced by Orbital Degrees of Freedom in Models for Manganites with Jahn-Teller Phonons

The 2-orbital Kondo model with classical Jahn-Teller phonons is studied using Monte Carlo techniques. The observed phase diagram is rich and includes a novel regime of phase separation induced by the orbital degrees of freedom. Experimental consequences of our results are discussed. In addition, the optical conductivity $\sigma \left(\omega \right)$ of the model is presented. It is shown to have several similarities with experimental measurements for manganites.