Momentum Distribution Functions in a One-Dimensional Extended Periodic Anderson Model

We study the momentum distribution of the electrons in an extended periodic Anderson model, where the interaction, U-cf, between itinerant and localized electrons is taken into account. In the symmetric half-filled model, due to the increase of the interorbital interaction, the felectrons become more and more delocalized, while the itinerancy of conduction electrons decreases. Above a certain value of U-cf the f electrons become again localized together with the conduction electrons. In the less than half-filled case, we observe that U-cf causes strong correlations between the f electrons in the mixed valence regime.