Atomistic simulations of long-range strain and spatial asymmetry effects in multimillion-atom single and double quantum dot nanostructures

The Nanoelectronic Modeling Tool NEMO-3D is a simulator providing quantitative estimates for the strain distribution and the singleparticle electronic structure of semiconductor nanodevices, such as self-assembled quantum dots, quantum wells and wires. Both strain and electronic structure are computed using semi-empirical nearest-neighbor tight-binding schemes implemented on the atomistic level. The software tool is parallelized using MPI, which makes it possible to treat multimillion-atom systems. This work reports on application of the NEMO-3D tool to single and coupled quantum dot nanostructures. The spatial extent and directionality of the strain field produced by a single InAs quantum dot embedded in the GaAs barrier material is explored. In the multidot systems, the electron and hole states are computed as a function of the interdot distance for vertically coupled double-dot molecules.