Anticrossing semiconducting band gap in nominally semimetallic InAs/GaSb superlattices

Abstract

While (Formula presented) (001) superlattices are semiconducting for (Formula presented) for (Formula presented) the InAs electron level (Formula presented) is below the GaSb hole level (Formula presented) so the system is converted to a nominal semimetal. At nonzero in-plane wave vectors (Formula presented) however, the wave functions (Formula presented) and (Formula presented) have the same symmetry, so they anticross. This opens up a “hybridization gap” at some (Formula presented) Using a pseudopotential plane-wave approach as well as a (pseudopotential fit) eight-band (Formula presented) approach, we predict the hybridization gap and its properties such as wave-function localization and out-of-plane dispersion. We find that recent model calculations underestimate this gap severely. © 2000 The American Physical Society.