The multi-band envelope function model was extended so as to treat twinning boundaries and more complex structures. A suitable Hamiltonian for the mutually rotated bulk parts was derived, and the effective scattering potential at the interface was modelled by using a state-dependent diagonal-matrix δ-function potential which was centered at the interface. The method was applied to a p-doped twinning superlattice that was based on Ge. The superlattice electronic structure exhibited zero-energy gaps, as well as folding and anti-crossing behavior, and agreed well with the results of pseudopotential calculations.

Multiband envelope function model of twinning boundaries and superlattices M.Tadić, Z.Ikonić: Solid State Communications, 1999, 110[7], 397-402