Non-equilibrium variable range hopping under DC bias in disordered electronic systems.

Variable range hopping is a mechanism of transport of electrons in a disordered electronic system which typically behave as insulators due to Anderson localization. In this study, we develop a theory of field assisted variable range hopping as a mechanism for insulator-metal transition in disordered systems. We develop a quantum mechanical model consisting of a 1D disordered insulating tight binding chain coupled to a dissipative fermionic bath and apply electric field across the chain. Our model shows the Mott 1/2-law in equilibrium. Under electric field we compute the IV characteristics using non-equilibrium green's function method which shows us a non-linear increase in the conductance with electric field. Our study indicates a disorder range in which the system shows variable range hopping and then goes into a transition from an typically insulator behavior to a metallic behavior.