Hybridization effect in the Falicov-Kimball model

The extended Falicov-Kimball model which contains hybridization between localized level and conduction band has been studied using the exact diagonalization method. We obtain the single-particle density of states and the valency from this method and analyze the behaviors of valence transition and activation gap. We find that the valence transition is continuous due to hybridization, while the activation gap closes discontinuously. Moreover, the onset of the valence transition and the closing point of the activation gap mismatch each other. Our result is well consistent with the recent experiment on SmB_6.