We use realistic pseudopotentials and a plane-wave basis to study the electronic structure of non-periodic, three-dimensional, 2000-atom (AlAs)_n/(GaAs)_m (001) superlattices, where the individual layer thicknesses n,m = {1,2,3} are randomly selected. We find that while the band gap of the equivalent (n = m = 2) ordered superlattice is indirect, random fluctuations in layer thicknesses lead to a direct gap in the planar Brillouin zone, strong wavefunction localization along the growth direction, short radiative lifetimes, and a significant band-gap reduction, in agreement with experiments on such intentionally grown disordered superlattices.
@article{arxiv.mtrl-th/9501004,
title = {Electronic structure of intentionally disordered AlAs/GaAs superlattices},
author = {K. A. Mader and L. -W. Wang and A. Zunger},
journal= {arXiv preprint arXiv:mtrl-th/9501004},
year = {2016}
}
Comments
10 pages, REVTeX and EPSF macros, 4 figures in postscript. e-mail to [email protected]