Electronic states of digital versus analog graded quantum wells

Abstract

A detailed comparative study is made of the electronic states of a digital quantum well (DQW) AlxGa(1-x)As/GaAs structure and its equivalent graded-compositoin analog quantum well with the purpose of finding out in detail to what extent the two structures have similar or different properties. The calculation is based on an empirical sp3s* tight-binding model with spin and is carried out by surface Green function matching employing an algorithm previously developed and used by the authors to study inhomogeneous systems. It is found that some basic features of the electronic states, notably the spatial distribution of their amplitude, can be drastically different, displaying the multiwell structure of the DQW. © 1995 The American Physical Society.