An electric-field driven Mott metal-insulator transition in correlated thin films: an inhomogeneous dynamical mean-field theory approach

Simulations are carried out based on the dynamical mean-field theory (DMFT) in order to investigate the properties of correlated thin films for various values of the chemical potential, temperature, interaction strength, and applied transverse electric field. Application of a sufficiently strong field to a thin film at half-filling leads to the appearance of conducting regions near the surfaces of the film, whereas in doped slabs the application of a field leads to a conductivity enhancement on one side of the film and a gradual transition to the insulating state on the opposite side. In addition to the inhomogeneous DMFT, an independent layer approximation (ILA) is considered, in which the properties of each layer are approximated by a homogeneous bulk environment. A comparison between the two approaches reveals that the less expensive ILA results are in good agreement with the DMFT approach, except close to the metal-to-insulator transition points and in the layers immediately at the film surfaces. The hysteretic behavior (memory effect) characteristic of the bulk doping driven Mott transition persists in the slab.