  A multiscale approach was adopted for the calculation of confined states in
self-assembled semiconductor quantum dots (QDs). While results close to
experimental data have been obtained with a combination of atomistic strain and
tight-binding (TB) electronic structure description for the confined quantum
states in the QD, the TB calculation requires substantial computational
resources. To alleviate this problem an integrated approach was adopted to
compute the energy states from a continuum 8-band k.p Hamiltonian under the
influence of an atomistic strain field. Such multi-scale simulations yield a
roughly six-fold faster simulation. Atomic-resolution strain is added to the
k.p Hamiltonian through interpolation onto a coarser continuum grid. Sufficient
numerical accuracy is obtained by the multi-scale approach. Optical transition
wavelengths are within 7% of the corresponding TB results with a proper
splitting of p-type sub-bands. The systematically lower emission wavelengths in
k.p are attributable to an underestimation of the coupling between the
conduction and valence bands.
