Ground-state electronic structure of quasi-one-dimensional wires in semiconductor heterostructures

E. T. Owen, C. H. W. Barnes

Published 2015-09-08Version 1

We use density functional theory, in the local density approximation, to determine the electronic structure of quasi-one-dimensional systems in realistic semiconductor heterostructure devices. We show that in a typical split-gate device, screening of electrons in the direction transverse to the wire is efficient and density fluctuations are washed out. For a top-gate, split-gate device in the low density, weak confinement regime, the exchange-correlation potential induces small density fluctuations as the electrons are depleted from the wire. At the weakest confinements and lowest densities, the electron density splits into two rows owing to electrostatic repulsion. An additional double-well external potential forms at very low density which enhances this row splitting phenomenon. The decoupling of the rows leads to a degeneracy in the bonding and anti-bonding Kohn-Sham sub-bands which produces an initial quantised conductance plateau of $2 \cdot 2 e^2 / h$.