Interplay Between the Electric Field and the Nonlinear Interaction in Ordered and Disordered Chains

A simple Kronig-Penney model is used to study the effect of nonlinear interactions on the electronic properties of ordered and disordered electrified chains. In the case of ordered potentials, we found that the nonlinearity suppresses the Wannier-Stark effect caused by the electric field. In the case of disordered potentials, the nonlinearity gives rise to a transition from superlocalized to weakly localized states.