The effects of the electron-phonon interaction on a Mott insulator

Using the dynamical mean field theory we show that an electron - phonon interaction can revert the energetic balance between the metallic state and the Mott insulator in the density-driven metal-insulator transition at zero temperature. We present results for the Hubbard - Holstein model where the Mott ground state is found for sufficiently high values of the electron - phonon coupling but still not in the polaronic regime.