Periodic Anderson Model With Holstein Phonons For The Description Of The Cerium Volume Collapse

Recent experiments have suggested that the electron-phonon coupling may play an important role in the gamma -> alpha volume collapse transition in cerium. A minimal model for the description of such a transition is the periodic Anderson model. In order to better understand the effect of the electron-phonon interaction on the volume collapse transition, we study the periodic Anderson model with coupling between Holstein phonons and electrons in the conduction band. We find that the electron-phonon coupling enhances the volume collapse, which is consistent with experiments in cerium. While we start with the Kondo volume collapse scenario in mind, our results capture some interesting features of the Mott scenario, such as a gap in the conduction electron spectra which grows with the effective electron-phonon coupling.