No abstract

We report the determination of parameters for the nearest-neighbor sp3s* tight-binding (TB) model for GaP, GaAs, GaSb, InP, InAs, and InSb at 0, 77, and 300 K based on the hybrid quasi-particle self-consistent GW (QSGW) calculation and their application to a type II (InAs)/(GaSb) superlattice. The effects of finite temperature have been incorporated empirically by adjusting the parameter for blending the exchange-correlation terms of the pure QSGW method and local density approximation, in addition to the usage of experimental lattice parameters. As expected, the TB band gap shrinks with temperature and asymptotically with superlattice period when it is large. In addition, a bell curve in the band gap in the case of small superlattice period and slight and remarkable anisotropy in effective masses of electron and hole, both predicted by the hybrid QSGW method, respectively, are reproduced.

We apply a hybrid quasiparticle self-consistent GW (QSGW) method, QSGW80+SO [Deguchi et al., Jpn. J. Appl. Phys. 55, 051201 (2016)], to a type-II superlattice, which is (InAs)n(GaSb)n (n = 1, 2, 3, and 4) for infrared sensors. For the first time, we successfully obtained reliable energy bands of the superlattice. The calculated band gaps as functions of n differ from those obtained on the basis of other theories, although they are consistent with the results of a recent photoluminescence experiment. Our real-space analysis of band-edge alignment obtained via core levels shows that the calculated band offset of InAs/GaSb for n = 4 is ∼0.5 eV, which is consistent with the value obtained in an X-ray photoelectron spectroscopy experiment.