INVESTIGATION OF LOCALIZATION IN AN INFINITE SUPERLATTICE

An exact method of determining localized electronic states within the framework of a Kronig-Penney-like model is presented for an infinite superlattice in which there exist slight fluctuations in layer thickness. It is shown that fluctuations in well layer thickness, regardless of degree, always produce localized states residing in the minigaps of a superlattice. Outside of the perturbed well, these localized wavefunctions decay exponentially in an oscillating pattern. The energies of these localized states are closely related to eigenvalues of a corresponding single quantum well. However, the localized well energy lies further from the minibands than the single quantum well energy. The present observations regarding an infinite superlattice are also compared with previous observations regarding a finite superlattice. © 1992.