Polaronic signatures in mid-infrared spectra: Prediction for LaMnO₃ and CaMno₃

Hole-doped LaMnO₃ and electron-doped CaMnO₃ form self-trapped electronic states. The spectra of these states have been calculated using a two orbital (Mn e_g Jahn-Teller) model, from which the nonadiabatic optical conductivity spectra are obtained. In both cases the optical spectrum contains weight in the gap region, whose observation will indicate the self-trapped nature of the carrier states. The predicted spectra are proportional to the concentration of the doped carriers in the dilute regime, with coefficients calculated with no further model parameters.