  First-principles full potential linearized augmented plane wave (FLAPW)
calculations have been performed for lattice-mismatched common-atom III-V
interfaces. In particular, we have examined the effects of epitaxial strain and
ordering direction on the valence band offset in [001] and [111] GaSb/InSb and
InAs/InSb superlattices, and found that the valence band maximum is always
higher at the InSb side of the heterojunction, except for the common-anion
system grown on an InSb substrate. The comparison between equivalent structures
having the same substrate lattice constant, but different growth axis, shows
that for comparable strain conditions, the ordering direction slightly
influences the band line-up, due to small differences of the charge
readjustment at the [001] and [111] interfaces. On the other hand, strain is
shown to strongly affect the VBO; in particular, as the pseudomorphic growth
conditions are varied, the bulk contribution to the band line-up changes
markedly, whereas the interface term is almost constant. On the whole, our
calculations yield a band line-up that decreases linearly as the substrate
lattice constant is increased, showing its high tunability as a function of
different pseudomorphic growth conditions. Finally, the band line-up at the
lattice matched InAs/GaSb interface determined using the transitivity rule gave
perfect agreement between predicted and experimental results.
