1999/08/25 by M. Stopa, Stopa, M.
Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/9908349
10 pages, 11 figures (included)
arxiv created 1999/08/25 · openalex publication_date 1999/08/25 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We calculate the electronic structure for a modulation doped and gated T-shaped quantum wire using density functional theory. We calculate the bandgap renormalization as a function of the density of conduction band electrons, induced by the donor layer and/or the gate, for the translationally invariant wire, incorporating all growth and geometric properties of the structure completely. We show that most of the bandgap renormalization arises from exchange-correlation effects, but that a small shift also results from the difference of wave function evolution between electrons and holes. We calculate the binding energy of excitons in the wire, which breaks translational invariance, using a simpler, cylindrical model of the wire. For a single hole and a one dimensional electron gas of density ne, screening of the exciton binding energy is shown to approximately compensate for bandgap renormalization, suggesting that the recombination energy remains approximately constant with ne, in agreement with experiment. We find that the nature of screening, as treated within our non-linear model, is significantly different from that of the various linear screening treatments, and the orthogonality of free carrier states with the bound electron states has a profound effect on the screening charge. We find that the electron and hole remain bound for all densities up to about 3 x 106 cm-1 and that, as ne increases from zero, trion and even ``quadron'' formation becomes allowed.