Pseudogap Formation in Models for Manganites

The density of states and one-particle spectral function A(k,ω) of the one- and two-orbital models for manganites, the latter with Jahn-Teller phonons, are evaluated using Monte Carlo techniques. Unexpectedly robust pseudogap (PG) features were found at low and intermediate temperatures, particularly at or near regimes where phase separation occurs as T→0. The PG follows the chemical potential and is caused by the formation of ferromagnetic metallic clusters in an insulating background. It is argued that PG formation should be generic of mixed-phase regimes. The results are in good agreement with recent photoemission experiments for La_1.2Sr_1.8Mn₂O₇.