Electronic superstructures in doped superlattices

Abstract

Using an approach based on the density functional, we show that the exchange-correlation contribution to the system energy can be bigger than the sum of the kinetic energy and the Hartree contribution due to redistribution of carriers over the quantum wells in doped composite superlattices at low temperatures and moderate impurity densities. As a result, the ground state of the system can correspond to an inhomogeneous electron distribution over the quantum wells. Conditions when the homogeneous state is stable against small and finite density fluctuations are determined, and a phase diagram is plotted. A nonlinear theory of the inhomogeneous state is considered.