Anisotropic defects and assisted scattering in InAs/GaSb superlattices

Heterostructures containing antimonide-based compounds received in the last decade much attention because of their potential for designing new devices. Moreover, some InAs/GaSb heterostructures are also topological insulators thus attracting interest for fundamental research. We performed a thorough multi-scale study of the structure and electronic states of InAs/GaSb surperlattices (SL). We have implemented the envelope function formalism for the calculation of the electronic states in these SL, taking into account the strong coupling between conduction and valence states. To improve the description of interface roughness, we performed atomistic simulations (using empirical interaction potentials as well as a Monte Carlo based algorithm) of the growth of InAs/GaSb short-period SL. In particular, we found that the simulated growth of InAs on GaSb along the usual [0,0,1] axis leads to the formation of elongated islands, one ML height, one ML thick, but with a much bigger average length along the direction [1,1,0]. Finally, we tackled the effect of the interface disorder on the electronic properties of these heterostructures. To this end, we present a model to perturbatively evaluating scattering rates by an inhomogeneous ensemble of defects with such a particular aspect ratio.