Oscillating electron mobility in GaAs/AlxGa1−xAs double quantum well structure under applied electric field

Abstract

We show that oscillation of low temperature electron mobility μ can be achieved in a single side barrier delta doped asymmetric GaAs/AlxGa1−xAs double quantum well structure. By applying an external electric field F the potential structure can be varied. Accordingly the system undergoes changes from single subband occupancy to double and then again to single subband occupancy. Under double subband occupancy the subband Fermi energies and wave functions exhibit nonmonotonous behavior leading to drastic cusp like changes in the intra- and intersubband scattering rate matrix elements as a function of F. We show that the resultant subband mobilities mediated by the intersubband effects are responsible for the oscillatory enhancement of μ. The oscillation of μ is mostly governed by the ionized impurity scattering and becomes prominent by increasing the well width and surface electron density. Our results can be utilized for low temperature nanoscale device applications.