Self-consistent simulation of quantum wires defined by local oxidation of Ga[Al]As heterostructures

TL;DR

This paper presents a self-consistent 2D simulation of quantum wires created by local oxidation on Ga[Al]As heterostructures, matching experimental results and analyzing key uncertainties affecting the electronic width.

Contribution

It introduces a density functional theory-based simulation approach for quantum wires defined by local oxidation, aligning well with experimental data and assessing influential parameters.

Findings

Simulation results agree with experimental measurements.

Oxide line depth significantly influences electronic width.

Background doping and shape also affect the results.

Abstract

We calculate the electronic width of quantum wires as a function of their lithographic width in analogy to experiments performed on nanostructures defined by local oxidation of Ga[Al]As heterostructures. Two--dimensional simulations of two parallel oxide lines on top of a Ga[Al]As heterostructure defining a quantum wire are carried out in the framework of Density Functional Theory in the Local Density Approximation and are found to be in agreement with measurements. Quantitative assessment of the influence of various experimental uncertainties is given. The most influential parameter turns out to be the oxide line depth, followed by its exact shape and the effect of background doping (in decreasing order).