Effect of parabolic potential on improvement of electron mobility in hybrid double quantum well structure

Abstract

We study the effect of parabolic potential on the improvement of low temperature multisubband electron mobility µ in a GaAs/AlxGa1-xAs hybrid double quantum well (HD) structure. The HD consists of a square and another parabolic well towards the bottom and top surfaces of the structure respectively. We calculate µ as function of well width w by considering different scattering mechanisms such as: Ionized Impurity (II-), Interface Roughness (IR-) and Alloy Disorder (AD-) scatterings. We show that µ is mostly decided by µII. We compare the results of µ with that of a square double quantum well (SD) and show that µ (HD) > µ (SD). This is due to the parabolic potential in HD structure which makes the distribution of wave functions asymmetric and hence affects the scattering rate matrix elements substantially. Our results can be utilized to study the properties of asymmetrically coupled quantum well systems.