Effect of Intersubband Interaction on Non-linear Electron Mobility in Asymmetric AlGaAs Parabolic Double Quantum Well Structure

We study the effect of inter-subband interaction on nonlinear electron mobility mu in asymmetric AlGaAs parabolic double quantum well structure. We take into account the ionized impurity (imp-) and alloy disorder (al-) scatterings for calculation of mu. We keep well width w2 towards the surface side fixed and vary mu with well width w1 along the substrate. The mobility mu enhances with w1. As w1 increases, there is a change in the number of subbands occupied, i.e., single, double and again single. When double subband occupied the inter-subband interaction induces nonlinear behavior of mu as a function of w1. This is due to the cusp like the fluctuation of imp- and al-intersubband scattering rate matrix elements.