J F. Diaz, W Jaskolski, J Planelles, Javier Aizpurua, Garnett W. Bryant
The electron energy structure of linear artificial molecules and one-dimensional chains formed of spherical semiconductor nanocrystals is investigated with and without and applied magnetic field. Both uniform and multilayer nanocrystals are studied. The calculations are performed within the effective mass model by numerically integrating the effective mass equation on a two-dimensional cylindrical grid. Density contours are presented to illustrate the transformation of states in systems of strongly interacting coupled quantum dots. Strong interaction between the quantum dot-quantum well structures in a chain of nanocrystals can lead to the formation of very narrow ground state miniband, well separated from the excited levels with the energies almost independent of the magnetic field. This effect is confirmed by calculations performed with the empirical tight-binding method. The effect of a random size of nonocrystals is also studied. If small fluctuations of size are included for a dense chain of nanocrystals, then delocalized states are still present in the spectrum. When the fluctuations reach 10%, strongly localized states are dominant.