Quantum dot defined in two-dimensional electron gas at n-AlGaAs/GaAs heterojunction: simulation of electrostatic potential and charging properties

摘要

We present a self-consistent Schroedinger-Poisson scheme for simulation ofelectrostatic quantum dots defined in gated two-dimensional electron gas formedat n-AlGaAs/GaAs heterojunction. The computational method is applied to aquantitative description of transport properties studied experimentally byElzermann et al. [Appl. Phys. Lett. {\bf 84}, 4617 (2004)]. Thethree-dimensional model describes the electrostatics of the entire device witha quantum dot that changes shape and floats inside a gated region when theapplied voltages are varied. Our approach accounts for the metal electrodes ofarbitrary geometry and configuration, includes magnetic field appliedperpendicular to the growth direction, electron-electron correlation in theconfined electron system and its interaction with the electron reservoirsurrounding the quantum dot. We calculate the electric field, the space chargedistribution as well as energies and wave functions of confined electrons todescribe opening of two transport channels between the reservoir and theconfined charge puddle. We determine the voltages for charging the dot with upto 4 electrons. The results are in a qualitative and quantitative agreement with theexperimental data.