An improved calculation model for analysis of [111] InGaAs/GaAs strained piezoelectric superlattices

We present a calculation model for an improved quantitative theoretical ana lysis of electronic and optical properties of strained-piezoelectric [111] InGaAs/GaAs superlattices (SLs), The model includes a full band-coupling be tween the four important energy bands: conduction, heavy, light, and spin s plit-off valence bands, The interactions between these and higher lying ban ds are treated by the k . p perturbation method. The model takes into accou nt the differences in the band and strain parameters of constituent materia ls of the heterostructures by transforming it into an SL potential in the l arger band-gap material region. It self-consistently solves an 8 x 8 effect ive-mass Schrodinger equation and the Hartree and exchange-correlation pote ntial equations through the variational procedure proposed recently by the present first author and applied to calculate optical matrix elements and s pontaneous emission rates. The model can be used to further elucidate the r ecent theoretical results and experimental observations of interesting prop erties of this type of quantum well and SL structures, including screening of piezoelectric held and its resultant optical nonlinearities for use in o ptoelectronic devices.