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

TL;DR

This study uses inhomogeneous dynamical mean-field theory to explore electric-field-induced Mott transitions in correlated thin films, revealing surface conducting regions and hysteresis effects.

Contribution

It introduces an inhomogeneous DMFT approach to analyze electric-field effects on Mott transitions in thin films, comparing it with an independent layer approximation.

Findings

Strong electric fields induce surface conduction in half-filled films.

Doped slabs show enhanced conductivity on one side and insulating transition on the other.

Hysteretic behavior persists in thin films, similar to bulk Mott transitions.

Abstract

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.