ELECTRONIC STATES OF DIGITAL VERSUS ANALOG GRADED QUANTUM-WELLS

A detailed comparative study is made of the electronic states of a dig ital quantum well (DQW) AlxGa(1-x)As/GaAs structure and its equivalent graded-composition analog quantum well with the purpose of finding ou t in detail to what extent the two structures have similar or differen t properties. The calculation is based on an empirical sp(3)s tight-b inding model with spin and is carried out by surface Green function ma tching employing an algorithm previously developed and used by the aut hors to study inhomogeneous systems. It is found that some basic featu res of the electronic states, notably the spatial distribution of thei r amplitude, can be drastically different, displaying the multiwell st ructure of the DQW.