Electronic structure and semiconductor-semimetal transition in InAs-GaSb superlattices

Abstract

Self-consistent electronic structure calculations in the envelope-function approximation are performed for InAs-GaSb superlattices, with a three-band $\overrightarrow{\mathrm{k}}·\overrightarrow{\mathrm{p}}$ formalism and suitable boundary conditions. The subband dispersion for $\overrightarrow{\mathrm{k}}$ not parallel to the growth axis, realistically computed for the first time, obeys a no-crossing rule which opens small (≲10 meV) gaps between conduction-band-like and valence-band-like subbands. It is therefore argued that the semimetallic behavior observed for periods $d\ge 180$ Å is dominated by extrinsic effects.