THE INFLUENCE OF IONIZED IMPURITIES ON ELECTRON ELECTRON DRAG BETWEEN PARALLEL 2-DIMENSIONAL GASES - MONTE-CARLO SIMULATION WITH MOLECULAR-DYNAMICS

We report an ensemble Monte Carlo simulation of Coulomb drag between parallel two-dimensional (2D) electron gases in an AlxGa1-xAs/GaAs double quantum well at 77 K The molecular dynamics technique is used to incorporate the many-particle Coulomb interaction including electron-electron as well as electron-ionized impurity interactions. Interactions of electrons with acoustic and polar-optical phonons are included using the usual Monte Carlo procedure. Simulation results show that remote donor scattering leads to a moderate decrease of the drag to drive velocity ratio. Background impurity scattering is found to lead to the increase of interwell momentum transfer rate with increasing density of background impurities. This effect is interpreted as the decreased carrier screening of the interwell Coulomb interaction. Finally, in the simulation without impurities, the effect of the separating barrier width on the Coulomb drag is discussed.