The tight binding method is employed to study the two-dimensional aspects of the electronic structure of InAs/GaSb(100) superlattices. Results are presented which show the spatially confined nature of the light hole, heavy hole and conduction bands. The hole states are found to be confined primarily on the GaSb side, whereas the conduction bands are confined to the InAs side. Effective masses in the plane of the superlattice are calculated. The conduction band mass is found to compare well with the appropriate value extracted from recent magnetoresistance measurements. Optical absorption data is used to determine the InAs conduction band to GaSb valence band edge discontinuity at the Γ-point. It is found that the former lies below the latter, qualitatively consistent with the electron affinity rule, but only by ∠ 60 meV. Reduction to this value from the affinity value of ∠ 140 meV is consistent with the affect of charge transfer. Finally, some comments regarding the variation, with thickness, of the relative and absolute positions of energies are made, particularly in light of the prevalent, though often ambiguous, practice of comparing projected regions of bulk energies with finite slab or superlattice band structures.
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Madhukar et al. (1979) studied this question.