Density-matrix description of a quantum dot system with variable lateral confinement in the single-electron tunneling regime

We consider a quantum dot system with variable confinement, realized by a vertical GaAs transistor with a lateral Schottky gate and an embedded asymmetrical AlGaAs/GaAs double barrier structure. The observed staircase current-voltage characteristics in the sub-Kelvin regime reflect the influence of the gate on the electronic structure. Many-body density-matrix simulations with a parabolic depletion model for the lateral gate are employed to interpret the experiments. (C) 2002 Elsevier Science B.V. All rights reserved.