k times p model for the energy dispersions and absorption spectra of InAs/GaSb type-II superlattices

We have fitted the k times p model derived recently by one of the authors [Klipstein, Phys. Rev. B 81, 235314 (2010) (http://dx.doi.org/10.1103/PhysRevB.81.235314)] to experimentally measured photoabsorption spectra at 77 and 300 K for representative InAs/GaSb superlattices with band-gap wavelengths between 4.3 and 10.5 mu m. We have also used the same model to predict the band-gap wavelengths of over 30 more superlattices, measured by photoluminescence spectroscopy. The maximum error is 0.6 mu m, which corresponds to an uncertainty of less than 0.4 ML in layer width. This is comparable with the experimental uncertainty in layer widths, determined by in situ beam-flux measurements in the growth reactor. The off-diagonal interface parameters alpha and beta are too small to be fitted with any accuracy and have negligible effect on the unpolarized photoabsorption spectra. We also propose values for the room-temperature Luttinger and interface parameters. The fitted unstrained InAs/GaSb band overlap is 0.142 eV.