Electrically driven insulator-to-metal transition in a correlated insulator: Electronic mechanism and thermal description

Motivated by the resistive switchings in transition-metal oxides (TMOs) induced by a voltage bias, we study the far-from-equilibrium dynamics of an electric-field-driven strongly correlated model featuring a first-order insulator-to-metal transition at equilibrium, namely the dimer-Hubbard model. We use a nonequilibrium implementation of the dynamical cluster approximation to access the steady-state spectral and transport properties. We show that the electric field can drive both metal-to-insulator and insulator-to-metal transitions. While they proceed by quite distinct mechanisms, specifically simple heating of the metal versus nonequilibrium effects in the correlated charge gap, we show that both of these nonequilibrium transitions can be unified in a single framework once the excitations are accounted for in terms of an effective temperature. This conceptual advance brings together the two sides of the long-lasting debate over the origins of the electrically driven resistive switching in TMOs.