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

TL;DR

This paper introduces a comprehensive self-consistent simulation method for electrostatic quantum dots in a 2D electron gas at n-AlGaAs/GaAs heterojunctions, capturing detailed electrostatics, electron interactions, and transport properties.

Contribution

It presents a three-dimensional Schroedinger-Poisson simulation approach that models quantum dot electrostatics, shape, and charging behavior, including magnetic fields and electron correlations, aligning well with experimental results.

Findings

Accurately predicts quantum dot charging with up to 4 electrons.

Describes the shape and electrostatics of the quantum dot under various voltages.

Provides detailed insights into transport channels and electron wave functions.

Abstract

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