Periodic Anderson model with electron-phonon correlated conduction band

Abstract

This Rapid Communication reports dynamical mean-field calculations for the periodic Anderson model in which the conduction band is coupled to phonons. Motivated in part by recent attention to the role of phonons in the $\ensuremath{\gamma}$-$\ensuremath{\alpha}$ transition in Ce, this model yields a rich and unexpected phase diagram which is of intrinsic interest. Specifically, above a critical value of the electron-phonon interaction, a first-order transition with two coexisting phases develops in the temperature-hybridization plane, which terminates at a second-order critical point. The coexisting phases display the familiar Kondo screened and local-moment character, yet they also exhibit pronounced polaronic and bipolaronic properties, respectively.