Electric-field-induced localization and oscillatory electro-optical properties of semiconductor superlattices.

We show that the application of an electric field $F$ along the growth axis of a semiconductor superlattice results in a strong localization of the eigenstates, a blue shift of the optical-absorption edge, and the presence of oscillations periodic in ${F}^{\ensuremath{-}1}$. These unique electro-optical properties are derived here within the framework of a tight-binding description of the envelope functions and also from numerical solutions of the Schr\"odinger equation for a finite set of coupled quantum wells.