Strain Effects on the Electronic Structure of Strongly Coupled Self-Assembled InAs/GaAs Quantum Dots: Tight-Binding Approach

Published

October 12, 2021

Author(s)

W Jaskolski, M Zielinski, Garnett W. Bryant, Javier Aizpurua

Abstract

We present an atomistic tight-binding study of the electronic structure and optical properties of vertically stacked, double, self-assembled, InAs/GaAs quantum dots. The investigated dots are lens-shaped and are situated on wetting layers. We study coupling and strain effects for closely spaced dots. For intermediate separation distances between the dots, the tight-binding theory confirms the effect of strain-induced localization of the ground hole state in the lower dot that is predicted in other approaches. However, the tight-binding calculations predict weaker localization at large separation distances and no localization for closely spaced and overlapping dots. An anomalous reversal of the bonding character of the ground hole state for large separation distances, found previously by us for unstrained systems, is present also for strained dots. We also show that in double quantum dots there may exist bound and localized electron and hole states with energies above the edge of the wetting layer continuum. The calculated redshift of the lowest optical transition for decreasing distance between the interacting dots agrees qualitatively with experimental data.

Citation

Physical Review B (Condensed Matter and Materials Physics)

Pub Type

Journals

Keywords

electronic structure, piezoelectricity strain, quantum dot, tight-binding Hamiltonian

Citation

Jaskolski, W. , Zielinski, M. , Bryant, G. and Aizpurua, J. (2021), Strain Effects on the Electronic Structure of Strongly Coupled Self-Assembled InAs/GaAs Quantum Dots: Tight-Binding Approach, Physical Review B (Condensed Matter and Materials Physics) (Accessed April 24, 2024)