Nonlinear Electronic Transport Equations for Tunneling Superlattices

We present a nonlinear electronic transport theory for a tunneling superlattice which is composed of interacting electrons with impurity and phonon scatterings. The theory is based on the Lei-Ting balance-equation method and a newly developed matrix separation technique for the density-correlation-function. Taking account of the overlap of the wave-functions between adjacent wells, the nonlinear dc resistivity in a transverse strong electric field is explicitly expressed in terms of the matrixdensity- correlation-function, which can be straightforwardly calculated in RPA as long as the single well wave function is given.