Exchange Energy Interactions in Quantum Well Heterostructures

Abstract

The influence of the exchange energy interaction on electronic subbands in a square well potential is investigated using a Kohn-Sham density functional approach. We concentrate on a layered AlGaAs/GaAs/AlGaAs system, the properties of which are observed as a function of well width, at absolute zero. Previous studies on exchange energy effects in quasi-2D (two dimensional) electron systems often use a local density functional formalism (Stern and Sarma, 1984) or, alternatively, the Slater approximation (Vx(r)^elater≈ n(r)^1/3) (Kaminskii, 1989). We, on the other hand, apply a recently proposed effective exchange potential Vx(z) (Krieger and others, 1990: see equation 3). The properties of Vx(z) make it interesting for future applications to heterojunction device simulations.